Human food

Human foodisfoodwhich is fit forhumanconsumption, and which humans willinglyeat. Food is a basic necessity of life, and humans typically seek food out as an instinctual response tohunger; however, not all things that areedibleconstitute as human food.
Humans eat various substances for energy, enjoyment andnutritionalsupport. These are usually of plant, animal, orfungalorigin, and contain essentialnutrients, such ascarbohydrates,fats,proteins,vitamins, andminerals. Humans are highly adaptableomnivores, and have adapted to obtain food in many different ecosystems. Historically,humanssecured food through two main methods:hunting and gatheringandagriculture. As agricultural technologies improved, humans settled intoagriculture lifestyleswith diets shaped by the agriculture opportunities in their region of the world. Geographic and cultural differences have led to the creation of numerouscuisinesandculinary arts, including a wide array ofingredients,herbs,spices,techniques, anddishes. As cultures have mixed through forces likeinternational tradeandglobalization, ingredients have become more widely available beyond their geographic and cultural origins, creating a cosmopolitan exchange of different food traditions and practices.
Today, the majority of thefood energyrequired by the ever-increasingpopulation of the worldis supplied by the industrialfood industry, which produces food withintensive agricultureand distributes it through complexfood processingandfood distributionsystems. This system of conventional agriculture relies heavily onfossil fuels, which means that the food and agricultural system is one of themajor contributors to climate change, accountable for as much as 37% of the totalgreenhouse gas emissions.Addressing thecarbon intensityof thefood systemandfood wasteareimportant mitigation measuresin the global response to climate change.
The food system has significant impacts on a wide range of other social and political issues, including:sustainability,biological diversity,economics,population growth,water supply, andaccess to food. Theright to foodis a "human right" derived from theInternational Covenant on Economic, Social and Cultural Rights(ICESCR), recognizing the "right to an adequatestandard of living, including adequate food", as well as the "fundamental rightto be free fromhunger". Because of these fundamental rights,food securityis often a priority international policy activity; for exampleSustainable Development Goal 2"Zero hunger" is meant to eliminatehungerby 2030.Food safetyandfood securityare monitored by international agencies like theInternational Association for Food Protection,World Resources Institute,World Food Programme,Food and Agriculture Organization, andInternational Food Information Council, and are often subject to national regulation by institutions, such as theFood and Drug Administrationin the United States.
Humans are omnivores finding sustenance in vegetables, fruits, cooked meat, milk, eggs, mushrooms and seaweed.Cerealgrain is astaple foodthat provides more food energy worldwide than any other type of crop.Corn (maize),wheat, andriceaccount for 87% of all grain production worldwide.Just over half of the world's crops are used to feed humans (55 percent), with 36 percent grown as animal feed and 9 percent forbiofuels.Fungi and bacteria are also used in the preparation offermentedfoods like bread, wine,cheeseandyogurt.
Humans eat thousands of plant species; there may be as many as 75,000 edible species ofangiosperms, of which perhaps 7,000 are often eaten.Most human plant-based food calories come from maize, rice, and wheat.Plants can be processed into bread, pasta, cereals, juices and jams, or raw ingredients such as sugar, herbs, spices and oils can be extracted.Oilseedsare often pressed to produce rich oils:sunflower,flaxseed,rapeseed(includingcanola oil) andsesame.
Animals may be used as foodeither directly or indirectly. This includes meat, eggs, shellfish and dairy products like milk and cheese.They are an important source of protein and are considered complete proteins for human consumption, as (unlike plant proteins) they contain all theamino acidsessential for the human body.Some cultures and people do not consume meat or animal food products for cultural, dietary, health, ethical, or ideological reasons.Vegetarianschoose to forgo food from animal sources to varying degrees.Vegansdo not consume any foods that containingredientsfrom an animal source.
Fish and other marine animals are harvested from lakes, rivers, wetlands, inland waters, coasts, estuaries, mangroves, near-shore areas, and marine and ocean waters. Although aquatic foods contribute significantly to the health of billions of people around the world, they tend to be undervalued nutritionally, primarily because their diversity is framed in a monolithic way as "seafood or fish." Worldwide, aquatic foods are available every season and are produced in a wide variety. Over 2,370 species are harvested from wild fisheries, and about 624 are farmed in aquaculture. Fish powder for infants, fish wafers for snacks, and fish chutneys have all been developed because marine foods are nutrient-dense.
Some animals, specifically humans, have five different types of tastes:sweet,sour,salty,bitter, andumami. As such animals haveevolved, the tastes that provide the most energy (sugarandfats) are the most pleasant to eat while others, such asbitter, are not enjoyable.Water, while important for survival, has no taste.Fats, on the other hand, especiallysaturated fats, are thicker and rich and are thus considered more enjoyable to eat.
Generally regarded as the most pleasant taste,sweetnessis almost always provided by a type of simplesugarsuch asglucoseorfructose, ordisaccharidessuch assucrose, a molecule combining glucose and fructose.Complex carbohydrates are long chains and do not have a sweet taste.
In the natural settings that human primate ancestors evolved in, sweetness intensity should indicateenergy density, while bitterness tends to indicatetoxicity.The high sweetness detection threshold and low bitterness detection threshold would have predisposed our primate ancestors to seek out sweet-tasting (and energy-dense) foods and avoid bitter-tasting foods.
Artificial sweeteners such assucraloseare used to mimic the sugar molecule, creating the sensation of sweetness, without the energy. Thesteviaplant contains a compound known assteviolwhich, when extracted, has 300 times the sweetness of sugar while having minimal impact on blood sugar.
Sournessis caused by the taste ofacids, such asvinegarin alcoholic beverages. Sour foods includecitrus, specificallylemons,limes, and to a lesser degreeoranges. Sour is evolutionarily significant as it is a sign of food that may have goneranciddue to bacteria.Many foods, however, are slightly acidic and help stimulate the taste buds and enhance flavour.
Saltinessis the taste ofalkali metalionssuch assodiumandpotassium. It is found in almost every food in low to moderate proportions to enhance flavour, although eating pure salt is regarded as highly unpleasant. There are many different types of salt, with each having a different degree of saltiness, includingsea salt,fleur de sel,kosher salt, mined salt, and grey salt.
Other than enhancing flavour, salty foods are significant for body needs and maintaining a delicateelectrolytebalance, which is thekidney's function. Salt may beiodized, meaningiodinehas been added to it. Iodine is a necessary nutrient for maintenance ofthyroidfunction, and the addition of iodine to salt became a public-health practice in the mid 20th century to preventiodine deficiencyand related diseases such asendemic goitre.
Some canned foods, notablysoupsor packagedbroths, tend to be high in salt as a means of preserving the food longer. Historically salt has long been used as a meat preservative as salt promotes water excretion. Similarly, dried foods also promote food safety.
Bitternessis a sensation often considered unpleasant and characterized by having a sharp, pungent taste. Unsweetened darkchocolate,caffeine, lemon rind, and some types of fruit are known to be bitter.
Umamihas been described as savoury and is characteristic of broths and cooked meats.Foods that have a strong umami flavor include meats,shellfish, fish (includingfish sauceand preserved fish such asMaldives fish, sardines, and anchovies), tomatoes, mushrooms,hydrolyzed vegetable protein,meat extract,yeast extract, cheeses, andsoy sauce.
Many scholars claim that the rhetorical function of food is to represent the culture of a country and that it can be used as a form of communication. According to Goode, Curtis and Theophano, food "is the last aspect of an ethnic culture to be lost".
Many cultures have a recognizable cuisine, a specific set ofcookingtraditions using various spices or a combination of flavours unique to that culture, which evolves. Other differences include preferences (hot or cold, spicy, etc.) and practices, the study of which is known asgastronomy. Many cultures have diversified their foods by utilizing preparation, cooking methods, and manufacturing. This also includes a complex food trade which helps the cultures to economically survive by way of food, not just by consumption.
Some popular types ofethnic foodsincludeItalian,French,Japanese,Chinese,American,Cajun,Thai,African,IndianandNepalese. Various cultures throughout the world study the dietary analysis of foodhabits. Whileevolutionarilyspeaking, as opposed to culturally, humans areomnivores, religion and social constructs such asmorality,activism, orenvironmentalismwill often affect which foods they will consume. Food is eaten and typically enjoyed through the sense oftaste, the perception of flavour from eating and drinking. Certain tastes are more enjoyable than others, for evolutionary purposes.
Aesthetically pleasing and eye-appealing food presentations can encourage people to consume food. A common saying is that people "eat with their eyes". Food presented in a clean and appetizing way will encourage a good flavour, even if unsatisfactory.
Textureplays a crucial role in the enjoyment of eating foods. Contrasts in textures, such as something crunchy in an otherwise smooth dish, may increase the appeal of eating it. Common examples include addinggranolatoyoghurt, addingcroutonsto asaladorsoup, and toasting bread to enhance its crunchiness for a smooth topping, such as jam or butter.
Another universal phenomenon regarding food is the appeal of contrast in taste and presentation. For example, such opposite flavours assweetnessandsaltinesstend to go well together, as inkettle cornandnuts.
While many foods can be eaten raw, many also undergo some form of preparation for reasons of safety,palatability,texture, orflavour. At the simplest level, this may involve washing, cutting, trimming, or adding other foods or ingredients, such as spices. It may also involve mixing, heating or cooling,pressure cooking, fermentation, or combination with other food. In a home, most food preparation takes place in akitchen. Some preparation is done to enhance thetasteor aesthetic appeal; other preparation may help topreservethe food; others may be involved in cultural identity. Amealis made up of food which is prepared to be eaten at a specific time and place.
The preparation of animal-based food usually involvesslaughter,evisceration, hanging, portioning, andrendering. In developed countries, this is usually done outside the home inslaughterhouses, which are used to process animals en masse for meat production. Many countries regulate their slaughterhouses by law. For example, the United States established theHumane Slaughter Actof 1958, which requires that an animal be stunned before killing. This act, like those in many countries, exempts slaughter following religious law, such askosher,shechita, anddhabīḥahhalal. Strict interpretations ofkashrutrequire the animal to be fully aware when its carotid artery is cut.
On the local level, a butcher may commonly break down larger animal meat into smaller manageable cuts, and pre-wrap them for commercial sale or wrap them to order in butcher paper. In addition, fish andseafoodmay be fabricated into smaller cuts by a fishmonger. However, fish butchery may be done on board a fishing vessel and quick-frozen for the preservation of the quality.
Certain cultures highlight animal and vegetable foods in araw state.Saladsconsisting of raw vegetables or fruits are common in many cuisines.SashimiinJapanese cuisineconsists of raw slicedfishor other meat, andsushioften incorporates raw fish or seafood.Steak tartareand salmon tartare are dishes made from diced or ground raw beef or salmon, mixed with various ingredients and served withbaguettes,brioche, orfrites.In Italy,carpacciois a dish of very thinly sliced rawbeef, drizzled with avinaigrettemade with olive oil.The health food movement known asraw foodismpromotes a mostlyvegandiet of raw fruits, vegetables, and grains prepared in various ways, including juicing, food dehydration, sprouting, and other methods of preparation that do not heat the food above 118 °F (47.8 °C).An example of a raw meat dish isceviche, a Latin American dish made with raw meat that is "cooked" from the highly acidic citric juice from lemons and limes along with other aromatics such as garlic.
The term "cooking" encompasses a vast range of methods, tools, and combinations of ingredients to improve the flavour or digestibility of food. Cooking technique, known asculinary art, generally requires the selection, measurement, and combining of ingredients in an ordered procedure to achieve the desired result. Constraints on success include the variability of ingredients, ambient conditions,tools, and the skill of the individual cook.The diversity of cooking worldwide is a reflection of the myriad nutritional, aesthetic, agricultural, economic, cultural, and religious considerations that affect it.
Cooking requires applying heat to a food which usually, though not always, chemically changes the molecules, thus changing its flavour,texture, appearance, and nutritional properties.Cooking certain proteins, such as egg whites, meats, and fish, denatures the protein, causing it to become firm. There is archaeological evidence of roasted foodstuffs atHomo erectuscampsites dating from 420,000 years ago.Boiling as a means of cooking requires a container, and has been practised at least since the 10th millennium BC with the introduction ofpottery.
There are many different types of equipment used for cooking.
Ovensare mostly hollow devices that get very hot, up to 500 °F (260 °C), and are used for baking or roasting and offer a dry-heat cooking method. Different cuisines will use different types of ovens. For example, Indian culture uses atandooroven, which is a cylindrical clay oven which operates at a single high temperature.Western kitchens use variable temperatureconvection ovens, conventional ovens,toaster ovens, or non-radiant heat ovens like themicrowave oven. Classic Italian cuisine includes the use of a brick oven containing burning wood. Ovens may be wood-fired, coal-fired,gas, electric, or oil-fired.
Various types of cooktops are used as well. They carry the same variations of fuel types as the ovens mentioned above. Cook-tops are used to heat vessels placed on top of the heat source, such as asauté pan, sauce pot,frying pan, orpressure cooker. These pieces of equipment can use either a moist or dry cooking method and include methods such assteaming,simmering,boiling, andpoachingfor moist methods, while the dry methods includesautéing,pan frying, anddeep-frying.
In addition, many cultures use grills for cooking. Agrilloperates with a radiant heat source from below, usually covered with a metal grid and sometimes a cover. An open-pit barbecue in the American south is one example along with the American-style outdoor grill fueled by wood, liquid propane, or charcoal along with soaked wood chips for smoking.AMexicanstyle of barbecue is calledbarbacoa, which involves the cooking of meats such as whole sheep over an open fire. In Argentina, anasado(Spanish for "grilled") is prepared on a grill held over an open pit or fire made upon the ground, on which a whole animal or smaller cuts are grilled.
Restaurantsemploychefsto prepare the food, andwaitersto serve customers at the table.The term restaurant comes from an old term for a restorativemeat broth; this broth (or bouillon) was served in elegant outlets in Paris from the mid 18th century.These refined "restaurants" were a marked change from the usual basic eateries such as inns and taverns,and some had developed from earlyParisian cafés, such asCafé Procope, by first serving bouillon, then adding other cooked food to their menus.
Commercial eateries existed during theRoman period, with evidence of 150 "thermopolia", a form of fast food restaurant, found inPompeii,and urban sales of prepared foods may have existed inChinaduring theSong dynasty.
In 2005, the population of the United States spent $496 billion on out-of-home dining. Expenditures by type of out-of-home dining were as follows: 40% in full-service restaurants, 37.2% in limited-service restaurants (fast food), 6.6% in schools or colleges, 5.4% in bars andvending machines, 4.7% in hotels and motels, 4.0% in recreational places, and 2.2% in others, which includes military bases.
Food systemshave complex economic and socialvalue chainsthat effect many parts of the global economy.
Most food has always been obtained through agriculture. With increasing concern over both the methods and products of modernindustrial agriculture, there has been a growing trend towardsustainable agriculturalpractices. This approach, partly fueled by consumer demand, encouragesbiodiversity, local self-reliance andorganic farmingmethods.Major influences on food production include international organizations (e.g. theWorld Trade OrganizationandCommon Agricultural Policy), national government policy (or law), and war.
Several organisations have begun calling for a new kind of agriculture in whichagroecosystemsprovide food but also support vitalecosystemservices so thatsoil fertilityandbiodiversityare maintained rather than compromised. According to theInternational Water Management InstituteandUNEP, well-managed agroecosystems not only provide food, fibre and animal products, they also provide services such asflood mitigation,groundwater recharge,erosion controland habitats for plants, birds, fish and other animals.
Packaged foods are manufactured outside the home for purchase. This can be as simple as abutcherpreparing meat or as complex as a modern internationalfood industry. Early food processing techniques were limited by available food preservation, packaging, and transportation. This mainly involvedsalting,curing, curdling,drying,pickling,fermenting, andsmoking.Food manufacturing arose during theIndustrial Revolutionin the 19th century.This development took advantage of newmass marketsand emerging technology, such asmilling, preservation,packagingandlabeling, and transportation. It brought the advantages of pre-prepared time-saving food to the bulk of ordinary people who did not employ domestic servants.
At the start of the 21st century, a two-tier structure has arisen, with a few international food processing giants controlling a wide range of well-known food brands. There also exists a wide array of small local or national food processing companies.Advanced technologies have also come to change food manufacturing. Computer-based control systems, sophisticatedprocessingand packaging methods, andlogisticsanddistributionadvances can enhance product quality, improvefood safety, and reduce costs.
TheWorld Bankreported that the European Union was the top food importer in 2005, followed at a distance by the US and Japan.Britain's need for food was especially well-illustrated inWorld War II.  Despite the implementation offood rationing, Britain remained dependent on food imports and the result was a long-term engagement in theBattle of the Atlantic.
Food is traded and marketed on a global basis. The variety and availability of food is no longer restricted by the diversity of locally grown food or the limitations of the local growing season.Between 1961 and 1999, there was a 400% increase in worldwide food exports.Some countries are now economically dependent on food exports, which in some cases account for over 80% of all exports.
In 1994, over 100 countries became signatories to theUruguay Roundof theGeneral Agreement on Tariffs and Tradein a dramatic increase intrade liberalization. This included an agreement to reduce subsidies paid to farmers, underpinned by theWTOenforcement ofagricultural subsidy,tariffs, importquotas, and settlement of trade disputes that cannot be bilaterally resolved.Where trade barriers are raised on the disputed grounds of public health and safety, the WTO refer the dispute to theCodex AlimentariusCommission, which was founded in 1962 by the United NationsFood and Agriculture Organizationand the World Health Organization. Trade liberalization has greatly affected world food trade.
Food marketing brings together the producer and the consumer. The marketing of even a single food product can be a complicated process involving many producers and companies. For example, 56 companies are involved in making onecanof chicken noodle soup. These businesses include not only chicken and vegetable processors but also the companies that transport the ingredients and those that print labels and manufacture cans.The food marketing system is the largest direct and indirect non-government employer in the United States.
In the pre-modern era, the sale of surplus food took place once a week when farmers took their wares on market day into the local village marketplace. Here food was sold togrocersfor sale in their local shops for purchase by local consumers.With the onset of industrialization and the development of the food processing industry, a wider range of food could be sold and distributed in distant locations. Typically early grocery shops would be counter-based shops, in which purchasers told the shopkeeper what they wanted so that the shopkeeper could get it for them.
In the 20th century,supermarketswere born. Supermarkets brought with them aselfserviceapproach to shopping usingshopping cartsand were able to offer quality food at a lower cost througheconomies of scaleand reduced staffing costs. In the latter part of the 20th century, this has been further revolutionized by the development of vast warehouse-sized, out-of-town supermarkets, selling a wide range of food from around the world.
Unlike food processors, food retailing is a two-tier market in which a small number of very largecompaniescontrol a large proportion of supermarkets. The supermarket giants wield great purchasing power over farmers and processors, and strong influence over consumers. Nevertheless, less than 10% ofconsumer spendingon food goes to farmers, with larger percentages going toadvertising, transportation, and intermediate corporations.
Access to food is an economical and a sociological issue. Disadvantaged people typically live further away from providers of healthy food than themiddle class. A study of 94 million visits to food retailers showed that Americans travel a median distance of 5.95 km (3.7 miles) each time they buy food.
Because of its centrality to human life, problems related to access, quality and production of food effect every aspect of human life.
Between the extremes of optimal health and death fromstarvationormalnutrition, there is an array of disease states that can be caused or alleviated by changes in diet. Deficiencies, excesses, and imbalances in diet can produce negative impacts on health, which may lead to various health problems such asscurvy,obesity, orosteoporosis,diabetes,cardiovascular diseasesas well as psychological and behavioral problems. The science of nutrition attempts to understand how and why specific dietary aspects influence health.
Nutrients in food are grouped into several categories. Macronutrients are fat, protein, and carbohydrates. Micronutrients are themineralsandvitamins. Additionally, food contains water anddietary fiber.
As previously discussed, the body is designed bynatural selectionto enjoy sweet and fattening foods for evolutionary diets, ideal forhunters and gatherers. Thus, sweet and fattening foods in nature are typically rare and are very pleasurable to eat. In modern times these foods are easily available to consumers, which promotesobesityin adults and children alike.
Food deprivation leads to malnutrition and ultimatelystarvation. This is often connected withfamine, which involves the absence of food in entire communities. This can have a devastating and widespread effect on human health and mortality.Rationingis sometimes used to distribute food in times of shortage, most notably during times of war.
Starvation is a significant international problem. Approximately 815 million people are undernourished, and over 16,000 children die per day from hunger-related causes.Food deprivation is regarded as a deficit need inMaslow's hierarchy of needsand is measured usingfamine scales.
Some countries list a legal definition of food, often referring them with the wordfoodstuff. These countries list food as any item that is to be processed, partially processed, or unprocessed for consumption. The listing of items included as food includes any substance intended to be, or reasonably expected to be, ingested by humans. In addition to these foodstuffs, drink,chewing gum, water, or other items processed into said food items are part of the legal definition of food. Items not included in the legal definition of food includeanimal feed, live animals (unless being prepared for sale in a market), plants before harvesting, medicinal products,cosmetics,tobaccoand tobacco products,narcoticorpsychotropic substances, and residues and contaminants.
Food aidcan benefit people suffering from a shortage of food. It can be used to improve peoples' lives in the short term, so that a society can increase its standard of living to the point that food aid is no longer required.Conversely, badly managed food aid can create problems by disrupting local markets, depressing crop prices, and discouraging food production. Sometimes a cycle of food aid dependence can develop.Its provision, or threatened withdrawal, is sometimes used as a political tool to influence the policies of the destination country, a strategy known asfood politics. Sometimes, food aid provisions will require certain types of food be purchased from certain sellers, and food aid can be misused to enhance the markets of donor countries.International efforts to distribute food to the neediest countries are often coordinated by theWorld Food Programme.
Foodborne illness, commonly called "food poisoning", is caused bybacteria,toxins,viruses,parasites, andprions. Roughly 7 million people die of food poisoning each year, with about 10 times as many suffering from a non-fatal version.The two most common factors leading to cases of bacterial foodborne illness are cross-contamination of ready-to-eat food from other uncooked foods and improper temperature control. Less commonly, acute adverse reactions can also occur if chemical contamination of food occurs, for example from improper storage, or use of non-food grade soaps and disinfectants. Food can also be adulterated by a very wide range of articles (known as "foreign bodies") during farming, manufacture, cooking, packaging, distribution, or sale. These foreign bodies can include pests or their droppings, hairs, cigarette butts, wood chips, and all manner of other contaminants. Certain types of food can become contaminated if stored or presented in an unsafe container, such as a ceramic pot with lead-based glaze.
Food poisoninghas been recognized as a disease since as early as Hippocrates.The sale ofrancid, contaminated, or adulterated food was commonplace until the introduction ofhygiene, refrigeration, and vermin controls in the 19th century. Discovery of techniques for killing bacteria using heat, and othermicrobiologicalstudies by scientists such asLouis Pasteur, contributed to the modern sanitation standards that are ubiquitous in developed nations today. This was further underpinned by the work ofJustus von Liebig, which led to the development of modernfood storageandfood preservationmethods.In more recent years, a greater understanding of the causes of food-borne illnesses has led to the development of more systematic approaches such as theHazard Analysis and Critical Control Points(HACCP), which can identify and eliminate many risks.
Recommended measures for ensuring food safety include maintaining a clean preparation area with foods of different types kept separate, ensuring an adequate cooking temperature, and refrigerating foods promptly after cooking.
Foods that spoil easily, such asmeats,dairy, andseafood, must be prepared a certain way to avoid contaminating the people for whom they are prepared. As such, the rule of thumb is that cold foods (such as dairy products) should be kept cold and hot foods (such as soup) should be kept hot until storage. Cold meats, such as chicken, that are to be cooked should not be placed at room temperature for thawing, at the risk of dangerous bacterial growth, such asSalmonellaorE. coli.
Some people haveallergiesor sensitivities to foods that are not problematic to most people. This occurs when a person'simmune systemmistakes a certain food protein for a harmful foreign agent and attacks it. About 2% of adults and 8% of children have a food allergy.The amount of the food substance required to provoke a reaction in a particularly susceptible individual can be quite small. In some instances, traces of food in the air, too minute to be perceived through smell, have been known to provoke lethal reactions in extremely sensitive individuals. Common food allergens aregluten,corn,shellfish(mollusks),peanuts, andsoy.Allergens frequently produce symptoms such asdiarrhea,rashes, bloating,vomiting, andregurgitation. The digestive complaints usually develop within half an hour of ingesting theallergen.
Rarely, food allergies can lead to amedical emergency, such asanaphylactic shock,hypotension(low blood pressure), and loss of consciousness. An allergen associated with this type of reaction is peanut, althoughlatexproducts can induce similar reactions.Initial treatment is withepinephrine(adrenaline), often carried by known patients in the form of anEpi-penorTwinject.
Human diet was estimated to cause perhaps around 35% ofcancersin a human epidemiological analysis byRichard DollandRichard Petoin 1981.These cancers may be caused bycarcinogensthat are present in food naturally or as contaminants. Food contaminated with fungal growth may containmycotoxinssuch asaflatoxinswhich may be found in contaminated corn and peanuts.  Other carcinogens identified in food includeheterocyclic aminesgenerated in meat when cooked at high temperature,polyaromatic hydrocarbonsin charred meat and smoked fish, andnitrosaminesgenerated from nitrites used as food preservatives incured meatsuch asbacon.
Anticarcinogensthat may help prevent cancer can also be found in many foods especially fruit and vegetables.Antioxidantsare important groups of compounds that may help remove potentially harmful chemicals. It is however often difficult to identify the specific components in diet that serve to increase or decrease cancer risk since many foods, such as beef steak and broccoli, contain low concentrations of both carcinogens and anticarcinogens.There are many international certifications in the cooking field, such asMonde Selection, A.A. Certification, iTQi. They use high-quality evaluation methods to make the food safer.
Many cultures hold some food preferences and some foodtaboos. Dietary choices can also define cultures and play a role in religion. For example, onlykosher foodsare permitted byJudaism,halalfoods byIslam, and inHinduismbeefis restricted.In addition, the dietary choices of different countries or regions have different characteristics. This is highly related to a culture'scuisine.
Dietary habits play a significant role in the health and mortality of all humans. Imbalances between the consumed fuels and expended energy results in either starvation or excessive reserves ofadiposetissue, known as body fat.Poor intake of various vitamins and minerals can lead to diseases that can have far-reaching effects on health. For instance, 30% of the world's population either has, or is at risk for developing,iodine deficiency.It is estimated that at least 3 million children are blind due tovitamin Adeficiency.Vitamin Cdeficiency results inscurvy.Calcium,vitamin D, andphosphorusare inter-related; the consumption of each may affect the absorption of the others.Kwashiorkorandmarasmusare childhood disorders caused by lack of dietary protein.
Many individuals limit what foods they eat for reasons of morality or other habits. For instance,vegetarianschoose to forgo food from animal sources to varying degrees due to concerns about animal welfare and negative impacts on humans due toenvironmental impacts of animal agricultureamong other reasons. Others choose ahealthier diet, avoiding sugars or animal fats and increasing consumption of dietary fiber andantioxidantslikevarious polyphenols.Obesity, a serious problem in the world,leads to higher chances of developingheart disease,diabetes, cancer and many other diseases.More recently, dietary habits have been influenced by the concerns that some people have about possible impacts on health or the environment fromgenetically modified food.Further concerns about the impact of industrial farming onanimal welfare, human health, and theenvironmentare also affecting contemporary human dietary habits. This has in part led to the emergence of movements with a preference fororganicandlocal food.There is increasing interest and research about optimizing dietsfor life extension and improved healthspans.