Rice 101: Nutrition facts and health effects
One of the oldest cereal grains, rice (Oryza sativa) is believed to have been grown for at least 5000 years.
It is a staple food for more than half of the world's population, particularly those living in southern and eastern Asia.
White rice is the most commonly consumed type, but brown (whole grain) rice is becoming increasingly popular in some Western countries due to its health benefits.
Various products are made from rice. These include rice flour, rice syrup, rice bran oil, and rice milk.
It is usually white in color, but brown rice can come in a variety of shades; brown, reddish, purplish, or black.
Rice is composed of carbs, with small amounts of protein and virtually no fat.
The table below contains detailed information on all of the nutrients in 100 grams of short-grain, cooked white rice. (1)
Rice is primarily composed of carbs.
Starch is the most common form of carbohydrates in foods, made up of long chains of glucose known as amylose and amylopectin.
Amylose and amylopectin have different properties that may contribute to both the texture and digestibility of rice.
Rice that is high in amylose, such as basmati rice, does not stick together after cooking.
On the other hand, rice that is low in amylose and high in amylopectin is sticky after cooking.
Perfect for risottos and rice puddings, sticky rice (glutinous rice) is also preferred in Asian cooking because it is easy to eat with chopsticks (2).
High digestibility is one of the downsides of the carbs in sticky rice. For a high-carb food, good digestibility is not always favorable because it may cause an unhealthy spike in blood sugar, especially among diabetics.
Bottom Line: Rice is mainly composed of carbohydrates. Some types may cause unhealthy spikes in blood sugar, making them unsuitable for diabetics.
Brown rice contains a fair amount of fiber (1.8%), while white rice is very low in fiber (0.3%) (1).
One cup of boiled brown rice (195 grams) contains approximately 3.5 grams of fiber (1).
Varying amounts of resistant starch are also found in both white and brown rice.
Resistant starch helps feed the beneficial bacteria in the gut, stimulating their growth.
Aside from resistant starch, the fiber is concentrated in the bran, which has been stripped from white rice.
The bran is mainly composed of insoluble fibers, such as hemicellulose, and contains virtually no soluble fiber.
Bottom Line: White rice contains virtually no fiber, whereas brown rice is a good source. Both types may also contain varying amounts of resistant starch, which may promote colon health.
Vitamins and Minerals
The nutrient value of rice depends on the variety and cooking method.
Many vitamins and minerals are concentrated in the bran and germ, which are components of brown rice, but not white.
- Manganese: A trace mineral found in most foods, especially whole grains. It is essential for metabolism, growth, development, and the body's antioxidant system.
- Selenium: A mineral that is a component of selenoproteins, which have various important functions in the body (8).
- Thiamin: Also known as vitamin B1, thiamin is essential for metabolism and the function of the heart, muscles, and nervous system.
- Niacin: Also known as vitamin B3, niacin in rice is mostly in the form of nicotinic acid. Soaking rice in water before cooking may increase its absorption (2).
- Magnesium: Found in brown rice, magnesium is an important dietary mineral. It has been suggested that low magnesium levels may contribute to a number of chronic diseases (9).
- Copper: Often found in whole grains, copper is low in the Western diet. Poor copper status may have adverse effects on heart health (10).
Bottom Line: Rice is generally a poor source of vitamins and minerals. However, considerable amounts may be concentrated in the bran of brown rice.
Other Plant Compounds
A number of plant compounds are found in rice, some of which are linked with potential health benefits.
Pigmented rice, such as red-grained varieties, have been found to be particularly rich in antioxidants (11).
- Phytic acid: An antioxidant found in brown rice, phytic acid (phytate) impairs the absorption of dietary minerals, such as iron and zinc. It can be reduced by soaking, sprouting, and fermenting the rice before cooking (12).
- Lignans: Found in rice bran, lignans are converted to enterolactone by gut bacteria. Enterolactone is an isoflavone (phytoestrogen) that may have several health benefits (13, 14, 15).
- Ferulic acid: A strong antioxidant found in rice bran. May protect against various chronic diseases, such as cancer, diabetes, and cardiovascular disease (16, 17).
- 2-acetyl 1-pyrroline (2AP): An aromatic substance, responsible for the taste and smell of scented rice, such as jasmine and basmati rice (18).
Bottom Line: White rice is a poor source of antioxidants and other plant compounds. However, the bran of brown rice may be a good source of ferulic acid, lignans, and phytic acid.
White vs. Brown Rice
White rice is highly refined, polished, and stripped of its bran (seed coat) and germ (embryo).
Brown rice is an intact whole grain, containing both the bran and the germ. For this reason, brown rice contains substantially more fiber than white rice.
Being the most nutritious parts of the grain, the bran and germ are rich in fiber and several vitamins, minerals, and antioxidants.
Eating white rice may have an adverse effect on blood sugar balance, and should be avoided by people with diabetes.
Brown rice is clearly a winner when it comes to nutritional quality and health benefits.
Bottom Line: Brown rice is generally considered much healthier than white.
Health Benefits of Brown Rice
Aside from providing energy and basic nutrients, refined white rice does not have any health benefits.
On the other hand, regular consumption of brown (whole grain) rice can be beneficial.
One study followed 86,190 men for 5.5 years. Those who consumed one serving or more of whole-grain breakfast cereals every day had 20% lower risk of death from cardiovascular disease than those who never or rarely consumed whole grains (25).
Another study followed 75,521 women for 10 years. High whole grain intake was found to be linked with a 30% reduction in cardiovascular disease risk compared to low intake (24).
Keep in mind that all of these studies are observational. They show an association between whole grains and health, but cannot prove causation.
A randomized controlled trial in 21 Korean men and women, half of which were obese, studied the effect of high-fiber rice on risk factors for cardiovascular disease.
Taken together, eating brown rice and other whole grain cereals may have beneficial effects on heart health.
Bottom Line: Brown rice contains several heart-healthy nutrients, so it may help prevent heart disease.
Adverse Effects and Individual Concerns
Eating rice regularly may be of concern for some people, especially if it accounts for a large proportion of the daily food intake.
Type 2 Diabetes
Type 2 diabetes is a common condition, characterized by high levels of blood sugar.
One study in 64,227 Chinese women found that those who consumed 300 grams of rice per day had a 1.8 fold greater risk of becoming diabetic than those who consumed 200 grams per day (34).
The glycemic index is a measure of how foods affect the rise in blood sugar after a meal.
Studies indicate that high-glycemic foods increase the risk of type 2 diabetes (39).
One study in over 150 thousand men and women suggests that eating brown rice rather than white rice may cut the risk of becoming diabetic (36).
These effects are believed to be due to the fiber content of brown rice (45).
Taken together, eating white rice regularly may have adverse effects on blood sugar control, especially if you are diabetic.
On the other hand, eating fiber-rich whole grains instead of refined grains, may have substantial health benefits.
Bottom Line: High consumption of sticky white rice may raise the risk of type 2 diabetes.
Food contamination by heavy metals has become a serious concern worldwide.
Many studies have reported excessive amounts of heavy metals in rice from a number of countries - a particular concern where rice makes up a significant portion of people's diet.
Heavy metals are concentrated in the bran. For this reason, brown rice contains higher levels of heavy metals than white rice (21).
Arsenic is easily taken up by all types of cereal grains, but its accumulation seems to be greater in rice compared to other grains, such as wheat and barley (53).
The main sources of heavy metal pollution in soil and water are human activities; heavy industry, mining operations, car traffic, waste incineration, and use of fertilizers and pesticides (54, 55, 56).
Over time, excessive intake of heavy metals from contaminated food may have adverse health effects.
Eating rice grown near heavily polluted industrial or mining areas should be avoided. This also applies to other food crops, such as vegetables.
Bottom Line: Consumption of rice from polluted areas should be avoided. It may accumulate high levels of heavy metals, such as arsenic.
Antinutrients in Brown Rice
Brown rice is high in phytic acid (phytate), an antioxidant that impairs the absorption of iron and zinc from the digestive tract (15).
For this reason, phytic acid is often referred to as an antinutrient.
Phytic acid is found in all edible seeds, such as legumes, nuts, and whole grain cereals.
Eating high-phytate foods with most meals may contribute to mineral deficiencies over time.
However, this is rarely a concern in well balanced diets or for those who eat meat regularly. On the other hand, it may be a problem among vegetarians and in developing countries where diets are largely composed of high-phytate foods (57).
Several effective methods can be used to reduce the phytic acid content. These include soaking, sprouting, and fermenting the grains (12).
Bottom Line: Brown rice contains phytic acid, an antinutrient that impairs the absorption of iron and zinc from the same meal.
Rice is a popular cereal worldwide, especially in Asia.
White rice is the most commonly eaten type, but brown rice is becoming more common as a healthier alternative.
As a good source of several healthy minerals and antioxidants, brown rice may help prevent heart disease.
On the other hand, high consumption of white rice (especially sticky rice) has been associated with increased risk of type 2 diabetes.