96-680: A leek is a vegetable , a cultivar of Allium ampeloprasum , the broadleaf wild leek ( syn. Allium porrum ). The edible part of the plant is a bundle of leaf sheaths that is sometimes erroneously called a stem or stalk. The genus Allium also contains the onion , garlic , shallot , scallion , chives , and Chinese onion . Three closely related vegetables, elephant garlic , kurrat and Persian leek or tareh , are also cultivars of A. ampeloprasum , although different in their culinary uses. Historically, many scientific names were used for leeks, but they are now all treated as cultivars of A. ampeloprasum . The name leek developed from
192-416: A ketone ), the glycerol component of triglycerides can be converted into glucose , via gluconeogenesis by conversion into dihydroxyacetone phosphate and then into glyceraldehyde 3-phosphate , for brain fuel when it is broken down. Fat cells may also be broken down for that reason if the brain's needs ever outweigh the body's. Triglycerides cannot pass through cell membranes freely. Special enzymes on
288-568: A "plant grown for food" was not established until the 18th century. In 1767, the word was specifically used to mean a "plant cultivated for food, an edible herb or root". The year 1955 saw the first use of the shortened, slang term "veggie". As an adjective , the word vegetable is used in scientific and technical contexts with a different and much broader meaning, namely of "related to plants" in general, edible or not—as in vegetable matter , vegetable kingdom , vegetable origin , etc. The exact definition of "vegetable" may vary simply because of
384-495: A day often being recommended. The word vegetable was first recorded in English in the early 15th century. It comes from Old French , and was originally applied to all plants; the word is still used in this sense in biological contexts. It derives from Medieval Latin vegetabilis "growing, flourishing" (i.e. of a plant), a semantic change from a Late Latin meaning "to be enlivening, quickening". The meaning of "vegetable" as
480-422: A decreased risk of certain cancers, including breast and colorectal cancer, while other studies found no associations with cancer risk. Polyunsaturated fat supplementation was found to have no effect on the incidence of pregnancy-related disorders, such as hypertension or preeclampsia , but may increase the length of gestation slightly and decreased the incidence of early premature births. Expert panels in
576-662: A few essential fatty acids that must be included in the diet. Dietary fats are also the carriers of some flavor and aroma ingredients and vitamins that are not water-soluble . In humans and many animals, fats serve both as energy sources and as stores for energy in excess of what the body needs immediately. Each gram of fat when burned or metabolized releases about nine food calories (37 kJ = 8.8 kcal ). Fats are also sources of essential fatty acids , an important dietary requirement. Vitamins A , D , E , and K are fat-soluble, meaning they can only be digested, absorbed, and transported in conjunction with fats. Fats play
672-507: A higher proportion of unsaturated acids, although there are exceptions such as coconut oil and palm kernel oil . Foods containing unsaturated fats include avocado , nuts , olive oils , and vegetable oils such as canola . Many scientific studies have found that replacing saturated fats with cis unsaturated fats in the diet reduces risk of cardiovascular diseases (CVDs), diabetes , or death. These studies prompted many medical organizations and public health departments, including
768-501: A large fraction of the population in developing countries. Concerns were also expressed at a 2010 conference of the American Dietetic Association that a blanket recommendation to avoid saturated fats could drive people to also reduce the amount of polyunsaturated fats, which may have health benefits, and/or replace fats by refined carbohydrates — which carry a high risk of obesity and heart disease. For these reasons,
864-565: A leek as an "ancient tradition" in Henry V ( c. 1599 ). In the play, Henry V tells the Welsh officer Fluellen that he, too, is wearing a leek "for I am Welsh, you know, good countryman." The 1985 and 1990 British one pound coins bear the design of a leek in a coronet, representing Wales. One version of the 2013 British one pound coin shows a leek with a daffodil. Alongside the other national floral emblems of countries currently and formerly in
960-400: A precise botanical meaning, being a part that developed from the ovary of a flowering plant . This is considerably different from the word's culinary meaning. While peaches , plums , and oranges are "fruit" in both senses, many items commonly called "vegetables", such as eggplants , bell peppers , and tomatoes , are botanically fruits. The question of whether the tomato is a fruit or
1056-405: A process called lipolysis . They are subsequently moved to absorptive enterocyte cells lining the intestines. The triglycerides are rebuilt in the enterocytes from their fragments and packaged together with cholesterol and proteins to form chylomicrons . These are excreted from the cells and collected by the lymph system and transported to the large vessels near the heart before being mixed into
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#17328447078871152-555: A short period, whereas a temperature of −18 °C (0 °F) is required for longer-term storage. The enzyme action will merely be inhibited, and blanching of suitably sized prepared vegetables before freezing mitigates this and prevents off-flavors developing. Not all micro-organisms will be killed at these temperatures and after thawing the vegetables should be used promptly because otherwise, any microbes present may proliferate. Traditionally, sun drying has been used for some products such as tomatoes, mushrooms, and beans, spreading
1248-423: A significant relationship between saturated fat and high serum cholesterol levels, which in turn have been claimed to have a causal relation with increased risk of cardiovascular disease (the so-called lipid hypothesis ). However, high cholesterol may be caused by many factors. Other indicators, such as high LDL/HDL ratio, have proved to be more predictive. In a study of myocardial infarction in 52 countries,
1344-487: A thick porridge was made of emmer wheat or beans, accompanied by green vegetables but little meat, and fish was not esteemed. The Romans grew broad beans, peas, onions and turnips and ate the leaves of beets rather than their roots. Vegetables play an important role in human nutrition. Most are low in fat and calories but are bulky and filling. They supply dietary fiber and are important sources of essential vitamins, minerals, and trace elements. Particularly important are
1440-404: A tropical jungle clearing is thought to be the first example of agriculture; useful plant species were identified and encouraged to grow while undesirable species were removed. Plant breeding through the selection of strains with desirable traits such as large fruit and vigorous growth soon followed. While the first evidence for the domestication of grasses such as wheat and barley has been found in
1536-702: A vegetable found its way into the United States Supreme Court in 1893. The court ruled unanimously in Nix v. Hedden that a tomato is correctly identified as, and thus taxed as, a vegetable, for the purposes of the Tariff of 1883 on imported produce. The court did acknowledge, however, that, botanically speaking, a tomato is a fruit. Before the advent of agriculture , humans were hunter-gatherers . They foraged for edible fruit, nuts, stems, leaves, corms , and tubers and hunted animals for food. Forest gardening in
1632-458: A vegetable is harvested, it is cut off from its source of water and nourishment. It continues to transpire and loses moisture as it does so, a process most noticeable in the wilting of green leafy crops. Harvesting root vegetables when they are fully mature improves their storage life, but alternatively, these root crops can be left in the ground and harvested over an extended period. The harvesting process should seek to minimise damage and bruising to
1728-503: A vital role in maintaining healthy skin and hair , insulating body organs against shock, maintaining body temperature, and promoting healthy cell function. Fat also serves as a useful buffer against a host of diseases. When a particular substance, whether chemical or biotic, reaches unsafe levels in the bloodstream, the body can effectively dilute—or at least maintain equilibrium of—the offending substances by storing it in new fat tissue. This helps to protect vital organs, until such time as
1824-466: A water molecule H 2 O . Other less common types of fats include diglycerides and monoglycerides , where the esterification is limited to two or just one of glycerol's –OH groups. Other alcohols, such as cetyl alcohol (predominant in spermaceti ), may replace glycerol. In the phospholipids , one of the fatty acids is replaced by phosphoric acid or a monoester thereof. The benefits and risks of various amounts and types of dietary fats have been
1920-551: A weak atherogenic effect. Different saturated fatty acids have differing effects on various lipid levels. The evidence for a relation between saturated fat intake and cancer is significantly weaker, and there does not seem to be a clear medical consensus about it. Various animal studies have indicated that the intake of saturated fat has a negative effect on the mineral density of bones . One study suggested that men may be particularly vulnerable. Studies have shown that substituting monounsaturated fatty acids for saturated ones
2016-593: Is 83% water, 14% carbohydrates , 1% protein , and contains negligible fat (table). A 100-gram ( 3 + 1 ⁄ 2 oz) reference amount supplies 255 kilojoules (61 kcal) of food energy and is a rich source (20% or more of the Daily Value , DV) of vitamin K (45% DV) and manganese (23% DV). It is a moderate source (10–19% DV) of vitamin B6 , folate , vitamin C , and iron (table). The Hebrew Bible talks of חציר , identified by commentators as leek, and says it
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#17328447078872112-448: Is a triglyceride , an ester of the triple alcohol glycerol H(–CHOH–) 3 H and three fatty acids. The molecule of a triglyceride can be described as resulting from a condensation reaction (specifically, esterification ) between each of glycerol's –OH groups and the HO– part of the carboxyl group HO(O=)C− of each fatty acid, forming an ester bridge −O−(O=)C− with elimination of
2208-741: Is about 75% monounsaturated fat. The high oleic variety sunflower oil contains at least 70% monounsaturated fat. Canola oil and cashews are both about 58% monounsaturated fat. Tallow (beef fat) is about 50% monounsaturated fat, and lard is about 40% monounsaturated fat. Other sources include hazelnut , avocado oil , macadamia nut oil , grapeseed oil , groundnut oil ( peanut oil ), sesame oil , corn oil , popcorn , whole grain wheat , cereal , oatmeal , almond oil , hemp oil , and tea-oil camellia . Polyunsaturated fatty acids can be found mostly in nuts, seeds, fish, seed oils, and oysters . Food sources of polyunsaturated fats include: MUFAs (especially oleic acid) have been found to lower
2304-648: Is abundant in Egypt. Dried specimens from archaeological sites in ancient Egypt , as well as wall carvings and drawings, indicate that the leek was a part of the Egyptian diet from at least the second millennium BCE . Texts also show that it was grown in Mesopotamia from the beginning of the second-millennium BCE. Leeks were eaten in ancient Rome and regarded as superior to garlic and onions . The 1st century CE cookbook Apicius contains four recipes involving leeks. Raw leek
2400-470: Is another method of preserving vegetables for later use. Sauerkraut is made from chopped cabbage and relies on lactic acid bacteria which produce compounds that are inhibitory to the growth of other micro-organisms. In 2010, China was the largest vegetable producing nation, with over half the world's production. India, the United States, Turkey, Iran, and Egypt were the next largest producers. China had
2496-529: Is applied to plants collectively to refer to all edible plant matter, including the flowers , fruits , stems , leaves , roots , and seeds . An alternative definition of the term is applied somewhat arbitrarily, often by culinary and cultural tradition. It may exclude foods derived from some plants that are fruits, flowers , nuts , and cereal grains, but include savoury fruits such as tomatoes and courgettes , flowers such as broccoli , and seeds such as pulses . Originally, vegetables were collected from
2592-459: Is associated with increased daily physical activity and resting energy expenditure. More physical activity, less anger, and less irritability were associated with a higher-oleic acid diet than one of a palmitic acid diet. The most common fatty acids in human diet are unsaturated or mono-unsaturated. Monounsaturated fats are found in animal flesh such as red meat , whole milk products, nuts, and high fat fruits such as olives and avocados. Olive oil
2688-603: Is contrary to the suggestion that polyunsaturated fats are shown to be protective against insulin resistance. The large scale KANWU study found that increasing MUFA and decreasing SFA intake could improve insulin sensitivity, but only when the overall fat intake of the diet was low. However, some MUFAs may promote insulin resistance (like the SFAs), whereas PUFAs may protect against it. Levels of oleic acid along with other MUFAs in red blood cell membranes were positively associated with breast cancer risk. The saturation index (SI) of
2784-471: Is determined based upon the standard portion sizes typically consumed, as well as general nutritional content. Potatoes are not included in the count as they are mainly providers of starch. For most vegetables and vegetable juices, one serving is half of a cup and can be eaten raw or cooked. For leafy greens, such as lettuce and spinach , a single serving is typically a full cup. A variety of products should be chosen as no single fruit or vegetable provides all
2880-553: Is loose and drained well; they can be grown in the same regions where onions can be grown. Leeks may be seeded directly, but are more typically sown at high density in seed-beds before being transplanted into the field. This happens at 12 weeks, when they have reached the thickness of a pencil. The optimum temperature for growth is around 20 °C (68 °F). Leeks are more cold-tolerant than other cultivated Allium species and can be produced year-round in Europe. They tolerate standing in
2976-427: Is not a fruit or seed, but including mature fruits that are eaten as part of a main meal". Falling outside these definitions are edible fungi (such as edible mushrooms ) and edible seaweed which, although not parts of plants , are often treated as vegetables. In the latter-mentioned definition of "vegetable", which is used in everyday language, the words "fruit" and "vegetable" are mutually exclusive. "Fruit" has
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3072-521: Is partially modulated by dietary fat ratios ( omega−3 / 6 / 9 ) with both omega−3 and −9 thought to be anti-inflammatory, and omega−6 pro-inflammatory (as well as by numerous other dietary components, particularly polyphenols and exercise, with both of these anti-inflammatory). Although both pro- and anti-inflammatory types of fat are biologically necessary, fat dietary ratios in most US diets are skewed towards omega−6, with subsequent disinhibition of inflammation and potentiation of insulin resistance. This
3168-408: Is slowed. Thrips can be controlled by chemical pesticides and by intercropping with legumes or other plants. Leek cultivars may be treated as a single cultivar group , e.g., as A. ampeloprasum 'Leek Group'. The cultivars can be subdivided in several ways, but the most common types are "summer leeks", intended for harvest in the season when planted, and overwintering leeks, meant to be harvested in
3264-732: Is the largest producer of vegetables, and global trade in agricultural products allows consumers to purchase vegetables grown in faraway countries. The scale of production varies from subsistence farmers supplying the needs of their family for food, to agribusinesses with vast acreages of single-product crops. Depending on the type of vegetable concerned, harvesting the crop is followed by grading, storing, processing, and marketing. Vegetables can be eaten either raw or cooked and play an important role in human nutrition, being mostly low in fat and carbohydrates, but high in vitamins, minerals and dietary fiber . Many nutritionists encourage people to consume plenty of fruit and vegetables, five or more portions
3360-501: The ApoB / ApoA1 (related to LDL and HDL, respectively) ratio was the strongest predictor of CVD among all risk factors. There are other pathways involving obesity , triglyceride levels, insulin sensitivity , endothelial function , and thrombogenicity , among others, that play a role in CVD, although it seems, in the absence of an adverse blood lipid profile, the other known risk factors have only
3456-598: The Fertile Crescent in the Middle East, it is likely that various peoples around the world started growing crops in the period 10,000 BC to 7,000 BC. Subsistence agriculture continues to this day, with many rural farmers in Africa, Asia, South America, and elsewhere using their plots of land to produce enough food for their families, while any surplus produce is used for exchange for other goods. Throughout recorded history,
3552-505: The Incas subsisted on maize in the lowlands and potatoes at higher altitudes. They also used seeds from quinoa , supplementing their diet with peppers, tomatoes, and avocados. In Ancient China , rice was the staple crop in the south and wheat in the north, the latter made into dumplings , noodles , and pancakes . Vegetables used to accompany these included yams , soybeans , broad beans , turnips , spring onions , and garlic . The diet of
3648-460: The Mediterranean Sea area, includes more total fat than the diet of Northern European countries, but most of it is in the form of unsaturated fatty acids (specifically, monounsaturated and omega-3) from olive oil and fish, vegetables, and certain meats like lamb, while consumption of saturated fat is minimal in comparison. A 2017 review found evidence that a Mediterranean-style diet could reduce
3744-570: The Old English word lēac , from which the modern English name for garlic also derives. Lēac means 'onion' in Old English and is a cognate with languages based on Old Norse; Danish løg , Icelandic laukur , Norwegian løk and Swedish lök . German uses Lauch for leek; in Dutch, look is used for the whole onion genus, Allium . Leeks must be grown in soil that
3840-469: The World Health Organization (WHO), to officially issue that advice. Some countries with such recommendations include: A 2004 review concluded that "no lower safe limit of specific saturated fatty acid intakes has been identified" and recommended that the influence of varying saturated fatty acid intakes against a background of different individual lifestyles and genetic backgrounds should be
3936-407: The circulation . These metabolic activities are regulated by several hormones (e.g., insulin , glucagon and epinephrine ). Adipose tissue also secretes the hormone leptin . A variety of chemical and physical techniques are used for the production and processing of fats, both industrially and in cottage or home settings. They include: The pancreatic lipase acts at the ester bond, hydrolyzing
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4032-744: The rumen of these animals. CLA has two double bonds, one in the cis configuration and one in trans , which makes it simultaneously a cis - and a trans -fatty acid. Concerns about trans fatty acids in human diet were raised when they were found to be an unintentional byproduct of the partial hydrogenation of vegetable and fish oils. While these trans fatty acids (popularly called "trans fats") are edible, they have been implicated in many health problems. The hydrogenation process, invented and patented by Wilhelm Normann in 1902, made it possible to turn relatively cheap liquid fats such as whale or fish oil into more solid fats and to extend their shelf-life by preventing rancidification. (The source fat and
4128-401: The vitamin C in them degrades rapidly. A few products such as potatoes and onions have better keeping qualities and can be sold when higher prices may be available, and by extending the marketing season, a greater total volume of crop can be sold. If refrigerated storage is not available, the priority for most crops is to store high-quality produce, to maintain a high humidity level, and to keep
4224-855: The AHA estimated that replacement of saturated fat with polyunsaturated fat in the American diet could reduce the risk of cardiovascular diseases by 30%. The consumption of saturated fat is generally considered a risk factor for dyslipidemia —abnormal blood lipid levels, including high total cholesterol, high levels of triglycerides, high levels of low-density lipoprotein (LDL, "bad" cholesterol) or low levels of high-density lipoprotein (HDL, "good" cholesterol). These parameters in turn are believed to be risk indicators for some types of cardiovascular disease. These effects were observed in children too. Several meta-analyses (reviews and consolidations of multiple previously published experimental studies) have confirmed
4320-585: The Commonwealth or part of the United Kingdom (including the English Tudor Rose , Scottish thistle , Irish shamrock , Canadian maple leaf , and Indian lotus ), the Welsh leek appeared on the coronation gown of Elizabeth II . Norman Hartnell designed it; when Hartnell asked if he could exchange the leek for the more aesthetically pleasing Welsh daffodil, he was told no. Perhaps the most visible use of
4416-571: The U.S. Food and Drug Administration , for example, recommends to consume at least 10% (7% for high-risk groups) of calories from saturated fat, with an average of 30% (or less) of total calories from all fat. A general 7% limit was recommended also by the American Heart Association (AHA) in 2006. The WHO/FAO report also recommended replacing fats so as to reduce the content of myristic and palmitic acids, specifically. The so-called Mediterranean diet , prevalent in many countries in
4512-660: The United States and Europe recommend that pregnant and lactating women consume higher amounts of polyunsaturated fats than the general population to enhance the DHA status of the fetus and newborn. In nature, unsaturated fatty acids generally have double bonds in cis configuration (with the adjacent C–C bonds on the same side) as opposed to trans . Nevertheless, trans fatty acids (TFAs) occur in small amounts in meat and milk of ruminants (such as cattle and sheep), typically 2–5% of total fat. Natural TFAs, which include conjugated linoleic acid (CLA) and vaccenic acid , originate in
4608-473: The United States. These foods are commonly eaten raw and may become contaminated during their preparation by an infected food handler. Hygiene is important when handling foods to be eaten raw, and such products need to be properly cleaned, handled, and stored to limit contamination. The USDA Dietary Guidelines for Americans recommends consuming five to nine servings of fruit and vegetables daily. The total amount consumed will vary according to age and gender, and
4704-427: The actions of naturally-occurring enzymes and the spoilage caused by micro-organisms . Canning and freezing are the most commonly used techniques, and vegetables preserved by these methods are generally similar in nutritional value to comparable fresh products with regards to carotenoids , vitamin E , minerals . and dietary fiber . Canning is a process during which the enzymes in vegetables are deactivated and
4800-577: The ancient Egyptians was based on bread , often contaminated with sand which wore away their teeth. Meat was a luxury but fish was more plentiful. These were accompanied by a range of vegetables including marrows, broad beans, lentils, onions, leeks, garlic, radishes, and lettuces. The mainstay of the Ancient Greek diet was bread, and this was accompanied by goat's cheese, olives, figs, fish, and occasionally meat. The vegetables grown included onions, garlic, cabbages, melons, and lentils. In Ancient Rome ,
4896-860: The antioxidant vitamins A , C , and E . When vegetables are included in the diet, there is found to be a reduction in the incidence of cancer, stroke, cardiovascular disease, and other chronic ailments. Research has shown that, compared with individuals who eat less than three servings of fruits and vegetables each day, those that eat more than five servings have an approximately twenty percent lower risk of developing coronary heart disease or stroke. The nutritional content of vegetables varies considerably; some contain useful amounts of protein though generally they contain little fat , and varying proportions of vitamins such as vitamin A , vitamin K , and vitamin B 6 ; provitamins ; dietary minerals ; and carbohydrates . The consumption of crunchy and hard to chew foods, such as raw vegetables, during youth, while
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#17328447078874992-436: The blood. Various tissues can capture the chylomicrons, releasing the triglycerides to be used as a source of energy. Liver cells can synthesize and store triglycerides. When the body requires fatty acids as an energy source, the hormone glucagon signals the breakdown of the triglycerides by hormone-sensitive lipase to release free fatty acids. As the brain cannot utilize fatty acids as an energy source (unless converted to
5088-406: The bond and "releasing" the fatty acid. In triglyceride form, lipids cannot be absorbed by the duodenum . Fatty acids, monoglycerides (one glycerol, one fatty acid), and some diglycerides are absorbed by the duodenum, once the triglycerides have been broken down. In the intestine , following the secretion of lipases and bile , triglycerides are split into monoacylglycerol and free fatty acids in
5184-642: The bones are still growing, is needed for the human's, and other animals', jaws' proper development, and without their consumption, the jaws do not grow to their full size, thus not leaving enough room for the teeth to grow in correctly, causing crooked and impacted teeth. However, vegetables often also contain toxins and antinutrients which interfere with the absorption of nutrients. These include α-solanine , α-chaconine , enzyme inhibitors (of cholinesterase , protease , amylase , etc.), cyanide and cyanide precursors , oxalic acid , tannins and others. These toxins are natural defenses, used to ward off
5280-541: The botanical names of sixty-one species of plants used as vegetables along with the common names of the vegetables in English, French, and Russian. ISO 67.080.20 covers the storage and transport of vegetables and their derived products. Fat In nutrition , biology , and chemistry , fat usually means any ester of fatty acids , or a mixture of such compounds , most commonly those that occur in living beings or in food . The term often refers specifically to triglycerides (triple esters of glycerol ), that are
5376-527: The crop. Onions and garlic can be dried for a few days in the field and root crops such as potatoes benefit from a short maturation period in warm, moist surroundings, during which time wounds heal and the skin thickens up and hardens. Before marketing or storage, grading needs to be done to remove damaged goods and select produce according to its quality, size, ripeness, and color. All vegetables benefit from proper post harvest care. A large proportion of vegetables and perishable foods are lost after harvest during
5472-399: The field for an extended harvest, which takes place up to 6 months from planting. Leeks suffer from insect pests, including the thrips species Thrips tabaci and the leek moth . Leeks are also susceptible to leek rust ( Puccinia allii ). Damage from thrips is greatest when under water stress in hot, dry weather. In these conditions, insect reproduction occurs quickly while plant growth
5568-490: The focus in future studies. This advice is often oversimplified by labeling the two kinds of fats as bad fats and good fats , respectively. However, since the fats and oils in most natural and traditionally processed foods contain both unsaturated and saturated fatty acids, the complete exclusion of saturated fat is unrealistic and possibly unwise. For instance, some foods rich in saturated fat, such as coconut and palm oil, are an important source of cheap dietary calories for
5664-501: The highest area of land devoted to vegetable production, while the highest average yields were obtained in Spain and the Republic of Korea. The International Organization for Standardization (ISO) sets international standards to ensure that products and services are safe, reliable, and of good quality. There are a number of ISO standards regarding fruits and vegetables. ISO 1991-1:1982 lists
5760-431: The human diet from time immemorial . Some are staple foods but most are accessory foodstuffs, adding variety to meals with their unique flavors and at the same time, adding nutrients necessary for health. Some vegetables are perennials but most are annuals and biennials , usually harvested within a year of sowing or planting. Whatever system is used for growing crops, cultivation follows a similar pattern; preparation of
5856-408: The incidence of insulin resistance ; PUFAs (especially large amounts of arachidonic acid ) and SFAs (such as arachidic acid ) increased it. These ratios can be indexed in the phospholipids of human skeletal muscle and in other tissues as well. This relationship between dietary fats and insulin resistance is presumed secondary to the relationship between insulin resistance and inflammation , which
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#17328447078875952-442: The insects, predators and fungi that might attack the plant. Some beans contain phytohaemagglutinin , and cassava roots contain cyanogenic glycoside as do bamboo shoots . These toxins can be deactivated by adequate cooking. Green potatoes contain glycoalkaloids and should be avoided. Fruit and vegetables, particularly leafy vegetables, have been implicated in nearly half the gastrointestinal infections caused by norovirus in
6048-586: The layered structure of the leek. The different ways of preparing the vegetable are: Leeks are an ingredient of cock-a-leekie soup , leek and potato soup, and vichyssoise , as well as plain leek soup . Because of their symbolism in Wales (see below), they have come to be used extensively in that country's cuisine. Elsewhere in Britain, leeks have come back in favor only in the last 50 years, having been overlooked for several centuries. Raw leek (bulb and lower leaves)
6144-585: The leek, however, is as the cap badge of the Welsh Guards , a battalion within the Household Division of the British Army. In Romania, the leek is also widely considered a symbol of Oltenia , a historical region in the country's southwestern part. Vegetable Vegetables are parts of plants that are consumed by humans or other animals as food . The original meaning is still commonly used and
6240-411: The light green parts, and to a lesser extent, the dark green parts of the leaves. The dark green portion is usually discarded because it has a tough texture, but it can be sautéed or more commonly added to stock for flavor. A few leaves are sometimes tied with twine and other herbs to form a bouquet garni . Leeks are typically chopped into slices 5–10 mm thick. The slices tend to fall apart due to
6336-424: The main components of vegetable oils and of fatty tissue in animals; or, even more narrowly, to triglycerides that are solid or semisolid at room temperature, thus excluding oils . The term may also be used more broadly as a synonym of lipid —any substance of biological relevance, composed of carbon , hydrogen , or oxygen , that is insoluble in water but soluble in non-polar solvents . In this sense, besides
6432-419: The main components of common food products like milk , butter , tallow , lard , salt pork , and cooking oils . They are a major and dense source of food energy for many animals and play important structural and metabolic functions in most living beings, including energy storage, waterproofing, and thermal insulation . The human body can produce the fat it requires from other food ingredients, except for
6528-423: The many parts of a plant consumed as food worldwide—roots, stems, leaves, flowers, fruits , and seeds. The broadest definition is the word's use adjectivally to mean "matter of plant origin". More specifically, a vegetable may be defined as "any plant, part of which is used for food", a secondary meaning then being "the edible part of such a plant". A more precise definition is "any plant part consumed for food that
6624-504: The merits of substituting polyunsaturated fats for saturated fats. The effect of saturated fat on cardiovascular disease has been extensively studied. The general consensus is that there is evidence of moderate-quality of a strong, consistent, and graded relationship between saturated fat intake, blood cholesterol levels, and the incidence of cardiovascular disease. The relationships are accepted as causal, including by many government and medical organizations. A 2017 review by
6720-506: The micro-organisms present killed by heat. The sealed can excludes air from the foodstuff to prevent subsequent deterioration. The lowest necessary heat and the minimum processing time are used in order to prevent the mechanical breakdown of the product and to preserve the flavor as far as is possible. The can is then able to be stored at ambient temperatures for a long period. Freezing vegetables and maintaining their temperature at below −10 °C (14 °F) will prevent their spoilage for
6816-479: The nutrients needed for health. International dietary guidelines are similar to the ones established by the USDA. Japan , for example, recommends the consumption of five to six servings of vegetables daily. French recommendations provide similar guidelines and set the daily goal at five servings. In India, the daily recommendation for adults is 275 grams (9.7 oz) of vegetables per day. Vegetables have been part of
6912-1054: The object of much study, and are still highly controversial topics. There are two essential fatty acids (EFAs) in human nutrition: alpha-Linolenic acid (an omega-3 fatty acid ) and linoleic acid (an omega-6 fatty acid ). The adult body can synthesize other lipids that it needs from these two. Different foods contain different amounts of fat with different proportions of saturated and unsaturated fatty acids. Some animal products, like beef and dairy products made with whole or reduced fat milk like yogurt , ice cream , cheese and butter have mostly saturated fatty acids (and some have significant contents of dietary cholesterol ). Other animal products, like pork , poultry , eggs , and seafood have mostly unsaturated fats. Industrialized baked goods may use fats with high unsaturated fat contents as well, especially those containing partially hydrogenated oils , and processed foods that are deep-fried in hydrogenated oil are high in saturated fat content. Plants and fish oil generally contain
7008-416: The observed health impact of replacing dietary saturated fat with linoleic acid found that it increased rates of death from all causes, coronary heart disease, and cardiovascular disease. These studies have been disputed by many scientists, and the consensus in the medical community is that saturated fat and cardiovascular disease are closely related. Still, these discordant studies fueled debate over
7104-508: The offending substances can be metabolized or removed from the body by such means as excretion , urination , accidental or intentional bloodletting , sebum excretion, and hair growth. In animals, adipose tissue , or fatty tissue is the body's means of storing metabolic energy over extended periods of time. Adipocytes (fat cells) store fat derived from the diet and from liver metabolism . Under energy stress these cells may degrade their stored fat to supply fatty acids and also glycerol to
7200-575: The pattern was reversed: the Hungarian product containing twice the trans fat of the New York product. Even within the United States, there was variation, with fries in New York containing 30% more trans fat than those from Atlanta . Numerous studies have found that consumption of TFAs increases risk of cardiovascular disease. The Harvard School of Public Health advises that replacing TFAs and saturated fats with cis monounsaturated and polyunsaturated fats
7296-420: The pods with salt, but this method of preservation is unsuited to most vegetables. Marrows, beetroot, carrot, and some other vegetables can be boiled with sugar to create jams. Vinegar is widely used in food preservation ; a sufficient concentration of acetic acid prevents the development of destructive micro-organisms, a fact made use of in the preparation of pickles , chutneys and relishes. Fermentation
7392-432: The process were initially kept secret to avoid consumer distaste. ) This process was widely adopted by the food industry in the early 1900s; first for the production of margarine , a replacement for butter and shortening, and eventually for various other fats used in snack food, packaged baked goods, and deep fried products. Full hydrogenation of a fat or oil produces a fully saturated fat. However, hydrogenation generally
7488-413: The produce in the shade. Proper post-harvest storage aimed at extending and ensuring shelf life is best effected by efficient cold chain application. Cold storage is particularly useful for vegetables such as cauliflower, eggplant, lettuce, radish, spinach, potatoes, and tomatoes, the optimum temperature depending on the type of produce. There are temperature-controlling technologies that do not require
7584-552: The produce on racks and turning the crop at intervals. This method suffers from several disadvantages including lack of control over drying rates, spoilage when drying is slow, contamination by dirt, wetting by rain, and attack by rodents, birds, and insects. These disadvantages can be alleviated by using solar powered driers. The dried produce must be prevented from reabsorbing moisture during storage. High levels of both sugar and salt can preserve food by preventing micro-organisms from growing. Green beans can be salted by layering
7680-679: The rich have been able to afford a varied diet including meat, vegetables and fruit, but for poor people, meat was a luxury and the food they ate was very dull, typically comprising mainly some staple product made from rice, rye, barley, wheat, millet or maize. The addition of vegetable matter provided some variety to the diet. The staple diet of the Aztecs in Central America was maize and they cultivated tomatoes , avocados , beans , peppers , pumpkins , squashes , peanuts , and amaranth seeds to supplement their tortillas and porridge . In Peru,
7776-491: The risk of cardiovascular diseases, overall cancer incidence, neurodegenerative diseases, diabetes, and mortality rate. A 2018 review showed that a Mediterranean-like diet may improve overall health status, such as reduced risk of non-communicable diseases. It also may reduce the social and economic costs of diet-related illnesses. A small number of contemporary reviews have challenged this negative view of saturated fats. For example, an evaluation of evidence from 1966 to 1973 of
7872-532: The same membranes was inversely associated with breast cancer risk. MUFAs and low SI in erythrocyte membranes are predictors of postmenopausal breast cancer. Both of these variables depend on the activity of the enzyme delta-9 desaturase (Δ9-d). Results from observational clinical trials on PUFA intake and cancer have been inconsistent and vary by numerous factors of cancer incidence, including gender and genetic risk. Some studies have shown associations between higher intakes and/or blood levels of omega-3 PUFAs and
7968-486: The soil by loosening it, removing or burying weeds, and adding organic manures or fertilisers; sowing seeds or planting young plants; tending the crop while it grows to reduce weed competition, control pests, and provide sufficient water; harvesting the crop when it is ready; sorting, storing, and marketing the crop or eating it fresh from the ground. Different soil types suit different crops, but in general in temperate climates, sandy soils dry out fast but warm up quickly in
8064-416: The spring and are suitable for early crops, while heavy clays retain moisture better and are more suitable for late season crops. The growing season can be lengthened by the use of fleece , cloches , plastic mulch , polytunnels , and greenhouses . In hotter regions, the production of vegetables is constrained by the climate, especially the pattern of rainfall, while in temperate zones, it is constrained by
8160-409: The spring of the year following planting. Summer leek types are generally smaller than overwintering types; overwintering types are generally more strongly flavored. Cultivars include 'King Richard' and 'Tadorna Blue'. Leeks have a mild, onion-like taste. In its raw state, the vegetable is crunchy and firm. The edible portions of the leek are the white base of the leaves (above the roots and stem base),
8256-400: The storage life of food without noticeably changing its properties. The objective of preserving vegetables is to extend their availability for consumption or marketing purposes. The aim is to harvest the food at its maximum state of palatability and nutritional value, and preserve these qualities for an extended period. The main causes of deterioration in vegetables after they are gathered are
8352-455: The storage period. These losses may be as high as thirty to fifty percent in developing countries where adequate cold storage facilities are not available. The main causes of loss include spoilage caused by moisture, moulds, micro-organisms, and vermin. Storage can be short-term or long-term. Most vegetables are perishable and short-term storage for a few days provides flexibility in marketing. During storage, leafy vegetables lose moisture , and
8448-532: The temperature and day length. On a domestic scale, the spade, fork, and hoe are the tools of choice while on commercial farms a range of mechanical equipment is available. Besides tractors, these include ploughs , harrows , drills , transplanters , cultivators , irrigation equipment, and harvesters . New techniques are changing the cultivation procedures involved in growing vegetables with computer monitoring systems, GPS locators, and self-steer programs for driverless machines giving economic benefits. When
8544-946: The total fat in those foods containing man-made trans fats formed by partially hydrogenating plant fats may be trans fat. Baking shortenings, unless reformulated, contain around 30% trans fats compared to their total fats. High-fat dairy products such as butter contain about 4%. Margarines not reformulated to reduce trans fats may contain up to 15% trans fat by weight, but some reformulated ones are less than 1% trans fat. High levels of TFAs have been recorded in popular "fast food" meals. An analysis of samples of McDonald's French fries collected in 2004 and 2005 found that fries served in New York City contained twice as much trans fat as in Hungary , and 28 times as much as in Denmark , where trans fats are restricted. For Kentucky Fried Chicken products,
8640-415: The triglycerides, the term would include several other types of compounds like mono- and diglycerides , phospholipids (such as lecithin ), sterols (such as cholesterol ), waxes (such as beeswax ), and free fatty acids, which are usually present in human diet in smaller amounts. Fats are one of the three main macronutrient groups in human diet , along with carbohydrates and proteins , and
8736-439: The use of electricity such as evaporative cooling. Storage of fruit and vegetables in controlled atmospheres with high levels of carbon dioxide or high oxygen levels can inhibit microbial growth and extend storage life. The irradiation of vegetables and other agricultural produce by ionizing radiation can be used to preserve it from both microbial infection and insect damage, as well as from physical deterioration. It can extend
8832-453: The vegetable on their helmets in an ancient battle against the Saxons that took place in a leek field. The Elizabethan poet Michael Drayton stated, in contrast, that the tradition was a tribute to Saint David, who ate only leeks when he was fasting. The leek ( Welsh : cenhinen ) has been known to be a symbol of Wales for a long time; Shakespeare , for example, refers to the custom of wearing
8928-632: The walls of blood vessels called lipoprotein lipases must break down triglycerides into free fatty acids and glycerol. Fatty acids can then be taken up by cells via fatty acid transport proteins (FATPs). Triglycerides, as major components of very-low-density lipoprotein (VLDL) and chylomicrons , play an important role in metabolism as energy sources and transporters of dietary fat. They contain more than twice as much energy (approximately 9 kcal/g or 38 kJ /g) as carbohydrates (approximately 4 kcal/g or 17 kJ/g). The most common type of fat, in human diet and most living beings,
9024-510: The wild by hunter-gatherers and entered cultivation in several parts of the world, probably during the period 10,000 BC to 7,000 BC, when a new agricultural way of life developed. At first, plants that grew locally were cultivated, but as time went on, trade brought common and exotic crops from elsewhere to add to domestic types. Nowadays, most vegetables are grown all over the world as climate permits, and crops may be cultivated in protected environments in less suitable locations. China
9120-781: Was interrupted before completion, to yield a fat product with specific melting point, hardness, and other properties. Partial hydrogenation turns some of the cis double bonds into trans bonds by an isomerization reaction . The trans configuration is favored because it is the lower energy form. This side reaction accounts for most of the trans fatty acids consumed today, by far. An analysis of some industrialized foods in 2006 found up to 30% "trans fats" in artificial shortening, 10% in breads and cake products, 8% in cookies and crackers, 4% in salty snacks, 7% in cake frostings and sweets, and 26% in margarine and other processed spreads. Another 2010 analysis however found only 0.2% of trans fats in margarine and other processed spreads. Up to 45% of
9216-543: Was the favorite vegetable of the Emperor Nero , who consumed it in soup or oil, believing it beneficial to the quality of his voice. This earned him the nickname "Porrophagus" or "Leek Eater". The leek is one of the national emblems of Wales , and it or the daffodil (in Welsh, the daffodil is known as "Peter's leek", Cenhinen Bedr ) is worn on St. David's Day . According to one Welsh myth , King Cadwaladr of Gwynedd ordered his soldiers to identify themselves by wearing
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