Wheat is one of the world's most commonly consumed cereal grains.
It comes from a type of grass (Triticum) that is grown in countless varieties worldwide.
Bread wheat, or common wheat, is the most common species. Several other closely related species include durum, spelt, emmer, einkorn, and Khorasan wheat.
White and whole wheat flour are key ingredients in baked goods, such as bread. Other wheat-based foods include pasta, noodles, semolina, bulgur, and couscous.
Wheat is highly controversial because it contains a protein called gluten, which can trigger a harmful immune response in predisposed individuals.
However, for people who tolerate it, whole-grain wheat can be a rich source of various antioxidants, vitamins, minerals, and fibers.
Wheat is mainly composed of carbohydrates, but also has moderate amounts of protein.
The table below contains information on all the main nutrients in wheat ().
Like all cereal grains, wheat is mainly composed of carbs.
Starch is the predominant type of carbohydrate in the plant kingdom, and accounts for over 90% of the total carb content in wheat ().
The health effects of starch mainly depend on its digestibility, which determines its effect on blood sugar levels.
High digestibility may cause an unhealthy spike in blood sugar after a meal and have harmful effects on health, especially in people with diabetes.
Similar to white rice and potatoes, both white and whole wheat rank high on the glycemic index, making them unsuitable for diabetics (, ).
On the other hand, some processed wheat products, such as pasta, are digested less efficiently and therefore don't raise blood sugar levels to the same extent ().
Bottom Line: Carbs are the main nutritional component of wheat, which is generally considered unsuitable for people with diabetes.
Whole wheat is high in fiber, but refined wheat contains virtually no fiber.
The fiber content of whole-grain wheat ranges from 12-15% of the dry weight ().
Concentrated in the bran, most of the fibers are removed in the milling process and largely absent in refined flour.
The most common fiber in wheat bran is arabinoxylan (70%), which is a type of hemicellulose. The rest is mostly made up of cellulose and beta-glucan (, ).
These fibers are all insoluble. They pass through the digestive system almost intact, leading to increased fecal weight. Some of them also feed the friendly bacteria in the gut (, , ).
Wheat also contains small amounts of soluble fibers (fructans) that may cause digestive symptoms in people with irritable bowel syndrome ().
However, in those who tolerate it, wheat bran may have beneficial effects on gut health.
Bottom Line: Whole-grain wheat is a rich source of fiber, which may have positive effects on digestive health.
Proteins account for 7% to 22% of wheat's dry weight (, ).
Gluten, a large family of proteins, accounts for up to 80% of the total protein content.
Gluten is responsible for the unique elasticity and stickiness of wheat dough, the properties that make it so useful in breadmaking.
Wheat gluten can have adverse health effects in predisposed individuals.
Bottom Line: Wheat contains decent amounts of protein. It is mainly in the form of gluten, which may have adverse effects in people with celiac disease or gluten sensitivity.
Whole wheat is a good source of several vitamins and minerals.
As with most cereal grains, the amount of minerals depends on the mineral content of the soil that it is grown in.
- Selenium: A trace element that has various essential functions in the body. The selenium content of wheat depends on the soil, and is very low in some regions, such as in China (, ).
- Manganese: Found in high amounts in whole grains, legumes, fruits and vegetables, manganese may be poorly absorbed from whole wheat due to its phytic acid content ().
- Phosphorus: A dietary mineral that has an essential role in the maintenance and growth of body tissues.
- Copper: An essential trace element that is often low in the Western diet. Copper deficiency may have adverse effects on heart health ().
- Folate: One of the B-vitamins, folate is also known as folic acid or vitamin B9. It is considered particularly important during pregnancy ().
The most nutritious parts of the grain - the bran and the germ - are all removed during the milling and refining process, and are absent from white wheat.
Therefore, white wheat is relatively poor in many vitamins and minerals, compared to whole-grain wheat.
Because wheat often accounts for a large portion of people's food intake, flour is commonly enriched with vitamins and minerals.
In fact, enrichment of wheat flour is mandatory in many countries ().
In addition to the nutrients mentioned above, enriched wheat flour may be a good source of iron, thiamin, niacin, and vitamin B6. Calcium is often added as well.
Bottom Line: Whole wheat may be a decent source of several vitamins and minerals, including selenium, manganese, phosphorus, copper, and folate.
Most of the plant compounds in wheat are concentrated in the bran and the germ, parts of the grain that are absent from refined white wheat (, ).
The highest levels of antioxidants are found in the aleurone layer, a component of the bran.
Wheat aleurone is also sold as a dietary supplement ().
- Ferulic acid: The predominant antioxidant polyphenol found in wheat and other cereal grains (, , ).
- Phytic acid: Concentrated in the bran, phytic acid may impair the absorption of minerals, such as iron and zinc, from the same meal. Soaking, sprouting, and fermenting grains can degrade most of it (, ).
- Alkylresorcinols: Found in wheat bran, alkylresorcinols are a class of antioxidants that may have a number of health benefits ().
- Lignans: Another family of antioxidants present in wheat bran. Test-tube experiments indicate that lignans may help prevent colon cancer ().
- Wheat germ agglutinin: A lectin (protein) concentrated in wheat germ and blamed for a number of adverse health effects. However, lectins are inactivated with heat and not active in baked or cooked wheat products ().
- Lutein: An antioxidant carotenoid, responsible for the color of yellow durum wheat. High-lutein foods may improve eye health ().
Bottom Line: Wheat bran (present in whole wheat) may contain a number of healthy antioxidants, such as alkylresorcinols and lignans.
Refined white wheat does not have any beneficial health properties.On the other hand, eating whole-grain wheat may have several health benefits for those who can tolerate it, especially when it replaces white wheat.
Whole-grain wheat is rich in fibers, mostly insoluble, that are concentrated in the bran.
Studies indicate that components of wheat bran may function as prebiotics, feeding the beneficial bacteria residing in the gut ().
However, most of the bran passes virtually unchanged through the digestive system, increasing fecal weight (, ).
Wheat bran may also shorten the time it takes undigested material to travel through the digestive tract, while slowing down transit times that are very fast (, ).
One study found that bran can reduce the risk of constipation in children ().
However, depending on the underlying cause of the constipation, eating bran may not always be effective ().
Bottom Line: Fibers in whole wheat (or bran) may promote gut health.
Prevention of Colon Cancer
Colon cancer is the most common type of cancer in the digestive system.
Observational studies have linked whole grain consumption (including whole wheat) with reduced risk of colon cancer (, , ).
One observational study estimated that people on low-fiber diets could cut the risk of colon cancer by 40% by eating more fiber ().
This is supported by randomized controlled trials (), but not all studies have found a significant protective effect ().
One thing is clear, whole-grain wheat is rich in fiber and contains a number of antioxidants and phytonutrients that may help prevent colon cancer (, ).
Bottom Line: Whole wheat, or other whole-grain cereals rich in fiber, may cut the risk of colon cancer.
In many people, gluten may trigger a harmful immune response, a condition known as celiac disease.
Other types of gluten intolerance include non-celiac gluten sensitivity, which is of a different nature and has an unknown cause.
Celiac disease is a chronic condition, characterized by a harmful immune reaction to gluten.
An estimated 0.5-1% of individuals have celiac disease (, , ).
Gluten, the main family of proteins in wheat, can be divided into glutenins and gliadins, which are present in varying amounts in all types of wheat.
The gliadins are considered to be the main cause of celiac disease (, ).
Celiac disease causes damage to the small intestine, resulting in impaired absorption of nutrients.
Associated symptoms may be weight loss, bloating, flatulence, diarrhea, constipation, stomach pain, and fatigue (, ).
It has also been suggested that gluten may contribute to brain disorders, such as schizophrenia and epilepsy (, , ).
Einkorn, a primitive wheat variety, causes weaker reactions than other varieties, but is still not suitable for people with gluten intolerance ().
Adhering to a gluten-free diet is the only known treatment for celiac disease. Wheat is the main dietary source of gluten, but it can also be found in rye, barley and many processed foods.
Bottom Line: Wheat gluten may trigger celiac disease in predisposed individuals. Celiac disease is characterized by damage in the small intestine and impaired absorption of nutrients.
The number of people that follow a gluten-free diet exceeds those who have celiac disease.
Sometimes, the reason may be the mere belief that wheat and gluten are inherently harmful to health. In other cases, wheat or gluten may cause actual symptoms, similar to those of celiac disease.
This condition has been called gluten sensitivity, or non-celiac wheat sensitivity, and is defined as an adverse reaction to wheat without any autoimmune or allergic reactions (, , ).
Frequent symptoms of gluten sensitivity include abdominal pain, headache, fatigue, diarrhea, joint pain, bloating and eczema ().
One study indicates that, in some people, the symptoms of wheat sensitivity may be triggered by substances other than gluten ().
Digestive symptoms may be due to a family of soluble fibers in wheat, so-called fructans, which belong to a class of fibers known as FODMAPs.
High dietary intake of FODMAPs exacerbates irritable bowel syndrome, a condition that has symptoms similar to those of celiac disease ().
In fact, gluten or wheat sensitivity has been estimated to be present in approximately 30% of people suffering from irritable bowel syndrome (, ).
Bottom Line: Gluten sensitivity is different from celiac disease, but the symptoms are similar in many ways.
Irritable Bowel Syndrome (IBS)
Irritable bowel syndrome is a common condition, characterized by abdominal pain, bloating, irregular bowel habits, diarrhea, and constipation.
It is more common in people that suffer from anxiety and is often triggered by a stressful life event ().
Sensitivity to wheat is common among people with irritable bowel syndrome (, ).
One of the reasons for this may be that wheat contains soluble fibers called fructans, which are FODMAPs (, , ).
Diets that are high in FODMAPs may exercerbate the symptoms of irritable bowel syndrome ().
Although FODMAPs make symptoms worse, they are not considered to be the underlying cause of irritable bowel syndrome.
Studies indicate that irritable bowel syndrome may be associated with low-grade inflammation in the digestive tract (, ).
In one 6-week trial in 20 men and women with irritable bowel syndrome (IBS), eating Khorasan wheat (Kamut) instead of common wheat, lowered inflammation and alleviated many symptoms of IBS ().
It is unclear which properties of Khorasan wheat are responsible for these differences. This requires further study.
If you have irritable bowel syndrome, limiting wheat consumption may be a good idea.
Bottom Line: Wheat consumption may worsen the symptoms of irritable bowel syndrome (IBS).
Although whole-grain wheat may have some health benefits, many people need to eat less of it, or avoid it altogether.
Food allergy is a common condition, triggered by a harmful immune response to certain types of proteins in foods.
Gluten in wheat is a common allergen, affecting approximately 1% of children ().
In adults, allergy is most often reported among those who are regularly exposed to air-borne wheat dust.
Baker's asthma and inflammation inside the nose (rhinitis) are typical allergic reactions to wheat dust ().
Bottom Line: Some people are allergic to wheat and should avoid it.
Whole-grain wheat contains phytic acid (phytate), a nutrient that impairs the absorption of minerals, such as iron and zinc, from the same meal ().
For this reason, it has been referred to as an antinutrient.
This is usually not a problem in well-balanced diets, but may be a concern in diets that are largely based on cereal grains and legumes.
The phytic acid content of wheat can be reduced considerably by soaking and fermenting the grains ().
For example, the phytate content of fermented sourdough bread may be reduced by 90% ().
Bottom Line: Whole wheat contains phytic acid, an antinutrient that may impair the absorption of iron and zinc from the gut.
Spelt is a primitive variety of wheat, closely related to the common wheat.
It has been grown since ancient times and although its popularity declined during the past century, it has been making a comeback as a health food ().
Being close relatives, common whole wheat and spelt have similar nutritional profiles.
Both contain gluten. In fact, all varieties of wheat contain gluten in varying amounts, and are not suitable for people with gluten intolerance.
Their protein and fiber content is similar, although this depends on which varieties of spelt and common wheat are being compared (, , ).
There is one thing that seems to set them apart. Spelt may be richer in some minerals, such as zinc (, ).
In fact, studies indicate that modern wheat may be lower in minerals than many other primitive types of wheat (, ).
Other than having a higher mineral content, the health benefits of eating spelt, rather than whole-grain common wheat, are unclear.
Bottom Line: Spelt may have a higher mineral content than common wheat. This is unlikely to have any health relevance.
Wheat is among the world's most common foods. It is also one of the most controversial.
Many people are intolerant to gluten, and need to eliminate wheat from their diet altogether.
On the positive side, moderate consumption of fiber-rich whole wheat may be a healthy dietary choice for those who tolerate it well. It may improve digestive health and help prevent colon cancer.