Wednesday, December 2, 2009

Why Brown-But Not White-Rice is One of the World's Healthiest Foods

The difference between brown rice and white rice is not just color! A whole grain of rice has several layers. Only the outermost layer, the hull, is removed to produce what we call brown rice. This process is the least damaging to the nutritional value of the rice and avoids the unnecessary loss of nutrients that occurs with further processing. If brown rice is further milled to remove the bran and most of the germ layer, the result is a whiter rice, but also a rice that has lost many more nutrients. At this point, however, the rice is still unpolished, and it takes polishing to produce the white rice we are used to seeing. Polishing removes the aleurone layer of the grain-a layer filled with health-supportive, essential fats. Because these fats, once exposed to air by the refining process, are highly susceptible to oxidation, this layer is removed to extend the shelf life of the product. The resulting white rice is simply a refined starch that is largely bereft of its original nutrients.

Our food ranking system qualified brown rice as an excellent source of manganese, and a good source of the minerals selenium and magnesium. The complete milling and polishing that converts brown rice into white rice destroys 67% of the vitamin B3, 80% of the vitamin B1, 90% of the vitamin B6, half of the manganese, half of the phosphorus, 60% of the iron, and all of the dietary fiber and essential fatty acids. By law in the United States, fully milled and polished white rice must be "enriched" with vitamins B1, B3, and iron. But the form of these nutrients when added back into the processed rice is not the same as in the original unprocessed version, and at least 11 lost nutrients are not replaced in any form even with rice "enrichment."


Here are some of the ways in which the nutrients supplied by brown rice can make an important difference in your health:

Manganese-Energy Production Plus Antioxidant Protection

Just one cup of brown rice will provide you with 88.0% of the daily value for manganese. This trace mineral helps produce energy from protein and carbohydrates and is involved in the synthesis of fatty acids, which are important for a healthy nervous system, and in the production of cholesterol, which is used by the body to produce sex hormones. Manganese is also a critical component of a very important antioxidant enzyme called superoxide dismutase. Superoxide dismutase (SOD) is found inside the body's mitochondria (the oxygen-based energy factories inside most of our cells) where it provides protection against damage from the free radicals produced during energy production.

Women Who Eat Whole Grains Weigh Less

A study published in the American Journal of Clinical Nutrition underscores the importance of choosing whole grains such as brown rice rather than refined grain, i.e., white rice, to maintain a healthy body weight. In this Harvard Medical School / Brigham and Women's Hospital study, which collected data on over 74,000 female nurses aged 38-63 years over a 12 year period, weight gain was inversely associated with the intake of high-fiber, whole-grain foods but positively related to the intake of refined-grain foods. Not only did women who consumed more whole grains consistently weigh less than those who ate less of these fiber-rich foods, but those consuming the most dietary fiber from whole grains were 49% less likely to gain weight compared to those eating foods made from refined grains.

Brown Rice is Rich in Fiber and Selenium

For people worried about colon cancer risk, brown rice packs a double punch by being a concentrated source of the fiber needed to minimize the amount of time cancer-causing substances spend in contact with colon cells, and being a very good source of selenium, a trace mineral that has been shown to substantially reduce the risk of colon cancer.

In addition to supplying 14.0% of the daily value for fiber, a cup of cooked brown rice provides 27.3% of the DV for selenium, an important benefit since many Americans do not get enough selenium in their diets, yet this trace mineral is of fundamental importance to human health. Selenium is an essential component of several major metabolic pathways, including thyroid hormone metabolism, antioxidant defense systems, and immune function. Accumulated evidence from prospective studies, intervention trials and studies on animal models of cancer has suggested a strong inverse correlation between selenium intake and cancer incidence. Several mechanisms have been suggested to explain the cancer-preventive activities of selenium. Selenium has been shown to induce DNA repair and synthesis in damaged cells, to inhibit the proliferation of cancer cells, and to induce their apoptosis, the self-destruct sequence the body uses to eliminate worn out or abnormal cells.

In addition, selenium is incorporated at the active site of many proteins, including glutathione peroxidase, which is particularly important for cancer protection. One of the body's most powerful antioxidant enzymes, glutathione peroxidase is used in the liver to detoxify a wide range of potentially harmful molecules. When levels of glutathione peroxidase are too low, these toxic molecules are not disarmed and wreak havoc on any cells with which they come in contact, damaging their cellular DNA and promoting the development of cancer cells.

Not only does selenium play a critical role in cancer prevention as a cofactor of glutathione peroxidase, selenium also works with vitamin E in numerous other vital antioxidant systems throughout the body. These powerful antioxidant actions make selenium helpful in the prevention not only of cancer, but also of heart disease, and for decreasing the symptoms of asthma and the pain and inflammation of rheumatoid arthritis.

Lower Cholesterol with Whole Brown Rice

Here's yet another reason to rely on whole foods, such as brown rice, for your healthy way of eating. The oil in whole brown rice lowers cholesterol.

When Marlene Most and colleagues from Louisiana State University evaluated the effects of rice bran and rice bran oil on cholesterol levels in volunteers with moderately elevated cholesterol levels, they found that rice bran oil lowered their LDL (bad) cholesterol.

The study, published in the American Journal of Clinical Nutrition, was divided into two parts. First, 26 subjects ate a diet including 13-22g of dietary fiber each day for three weeks, after which 13 switched to a diet that added defatted rice bran to double their fiber intake for five weeks. In the second part of the study, a randomized crossover trial, 14 subjects ate a diet with rice bran oil for 10 weeks.

While the diet including only defatted rice bran did not lower cholesterol, the one containing rice bran oil lowered LDL cholesterol by 7%. Since all the diets contained similar fatty acids, the researchers concluded that the reduction in cholesterol seen in those receiving rice bran oil must have been due to other constituents such as the unsaponifiable compounds found in rice bran oil. The scientists suggest that the unsaponifiables present in rice bran oil could become important functional foods for cardiovascular health. But why extract just one beneficial compound from brown rice when you can reap all the cardioprotective benefits supplied by the matrix of nutrients naturally present in this delicious whole food? In addition to unsaponifiables, this whole grain also supplies hefty doses of heart-healthy fiber, magnesium, and B vitamins.

Significant Cardiovascular Benefits for Postmenopausal Women

Eating a serving of whole grains, such as brown rice, at least 6 times each week is an especially good idea for postmenopausal women with high cholesterol, high blood pressure or other signs of cardiovascular disease (CVD).

A 3-year prospective study of over 200 postmenopausal women with CVD, published in the American Heart Journal, shows that those eating at least 6 servings of whole grains each week experienced both:

Slowed progression of atherosclerosis, the build-up of plaque that narrows the vessels through which blood flows, and
Less progression in stenosis, the narrowing of the diameter of arterial passageways.
The women's intake of fiber from fruits, vegetables and refined grains was not associated with a lessening in CVD progression.

Lignans Protect against Heart Disease

One type of phytonutrient especially abundant in whole grains including brown rice are plant lignans, which are converted by friendly flora in our intestines into mammalian lignans, including one called enterolactone that is thought to protect against breast and other hormone-dependent cancers as well as heart disease. In addition to whole grains, nuts, seeds and berries are rich sources of plant lignans, and vegetables, fruits, and beverages such as coffee, tea and wine also contain some. When blood levels of enterolactone were measured in over 850 postmenopausal women in a Danish study published in the Journal of Nutrition, women eating the most whole grains were found to have significantly higher blood levels of this protective lignan. Women who ate more cabbage and leafy vegetables also had higher enterolactone levels.

Reduce Your Risk of Metabolic Syndrome

First we were told, "Don't eat fat, and you'll stay trim." After following this advice only to see obesity expand to never before seen proportions, we're told by the food gurus, "Eating fat is fine. Shun carbohydrates to stay slim."

In our opinion, neither piece of dietary advice is complete, accurate or likely to help us stay slim or healthy. Just as different kinds of fats have different effects in our bodies (e.g., saturated and trans fats are linked to increased risk for cardiovascular disease while omega-3 fats decrease cardiovascular disease risk), some carbohydrates, such as whole grains, are healthful while others, such as refined grains and the foods made from them, are not.

The latest research is clearly supporting this vital distinction. Refined grains and the foods made from them (e.g., white breads, cookies, pastries, pasta and rice) are now being linked not only to weight gain but to increased risk of insulin resistance (the precursor of type 2 diabetes) and the metabolic syndrome (a strong predictor of both type 2 diabetes and cardiovascular disease), while eating more wholegrain foods is being shown to protect against all these ills. Common features of the metabolic syndrome include visceral obesity (the "apple shaped" body), low levels of protective HDL cholesterol, high triglycerides, and high blood pressure.

In one of the most recent studies, which appeared in Diabetes Care, researchers who analyzed data on over 2,800 participants in the Framingham Offspring Study, found that the prevalence of both insulin resistance and the metabolic syndrome was significantly lower among those eating the most cereal fiber from whole grains compared to those eating the least.

Prevalence of the metabolic syndrome was 38% lower among those with the highest intake of fiber from whole grains. Conversely, study subjects whose diets had the highest glycemic index and glycemic load, both of which are typically low in whole foods and high in processed refined foods, were 141% more likely to have the metabolic syndrome compared to those whose diets had the lowest glycemic index and glycemic load. In other words, compared to those whose diets were primarily composed of whole high fiber foods: whole grains, legumes, vegetables and fruits.

The researchers concluded, "Given that both a high cereal fiber content and lower glycemic index are attributes of wholegrain foods, recommendation to increase wholegrain intake may reduce the risk of developing the metabolic syndrome." Our perspective at the World's Healthiest Foods is that a way of eating that relies on the healthiest foods from all the food groups-the whole foods that contain the healthiest fats, carbohydrates and proteins-is the most effective, intelligent, and most enjoyable way to not only lower your risk of developing the metabolic syndrome, but to stay slim, vital and attractive throughout a long and healthy life.

Brown Rice and Other Whole Grains Substantially Lower Type 2 Diabetes Risk

Brown rice and other whole grains are a rich source of magnesium, a mineral that acts as a co-factor for more than 300 enzymes, including enzymes involved in the body's use of glucose and insulin secretion.

The FDA permits foods that contain at least 51% whole grains by weight (and are also low in fat, saturated fat, and cholesterol) to display a health claim stating consumption is linked to lower risk of heart disease and certain cancers. Now, research suggests regular consumption of whole grains also reduces risk of type 2 diabetes. (van Dam RM, Hu FB, Diabetes Care).

In this 8-year trial, involving 41,186 particpants of the Black Women's Health Study, research data confirmed inverse associations between magnesium, calcium and major food sources in relation to type 2 diabetes that had already been reported in predominantly white populations.

Risk of type 2 diabetes was 31% lower in black women who frequently ate whole grains compared to those eating the least of these magnesium-rich foods. When the women's dietary intake of magnesium intake was considered by itself, a beneficial, but lesser- 19%- reduction in risk of type 2 diabetes was found, indicating that whole grains offer special benefits in promoting healthy blood sugar control. Daily consumption of low-fat dairy foods was also helpful, lowering risk of type 2 diabetes by 13%. Rice pudding-quickly made by simply adding low-fat milk, cinnamon, raisins, a little honey and 1/4 teaspoon of finely grated orange peel to a cup of cooked rice, then cooking over medium heat for 5 minutes-is a delicious way to enjoy both rice and dairy.

Tune Down and Bone Up on Brown Rice

Magnesium, another nutrient for which brown rice is a good source, has been shown in studies to be helpful for reducing the severity of asthma, lowering high blood pressure, reducing the frequency of migraine headaches, and reducing the risk of heart attack and stroke. How does magnesium accomplish all this? Magnesium helps regulate nerve and muscle tone by balancing the action of calcium. In many nerve cells, magnesium serves as Nature's own calcium channel blocker, preventing calcium from rushing into the nerve cell and activating the nerve. By blocking calcium's entry, magnesium keeps our nerves (and the blood vessels and muscles they ennervate) relaxed. If our diet provides us with too little magnesium, however, calcium can gain free entry, and nerve cells can become overactivated, sending too many messages and causing excessive contraction. Insufficient magnesium can thus contribute to high blood pressure, muscle spasms (including spasms of the heart muscle or the spasms of the airways symptomatic of asthma), and migraine headaches, as well as muscle cramps, tension, soreness and fatigue.

But that's far from all magnesium does for you. Magnesium, as well as calcium, is necessary for healthy bones. About two-thirds of the magnesium in the human body is found in our bones. Some helps give bones their physical structure, while the rest is found on the surface of the bone where it is stored for the body to draw upon as needed. Brown rice can help you keep those storage sites replenished and ready to meet your body's needs. A cup of brown rice will give you 21.0% of the daily value for magnesium.

In addition to the niacin it supplies, brown rice may also help raise blood levels of nitric oxide, a small molecule known to improve blood vessel dilation and to inhibit oxidative (free radical) damage of cholesterol and the adhesion of white cells to the vascular wall (two important steps in the development of atherosclerotic plaques). A study published in the British Journal of Nutrition suggests that diets high in rice protein can help protect against atherosclerosis by increasing blood levels of nitric oxide.

In this study, when researchers gave mice bred to be apoliprotein-E deficient a purified diet containing either casein, the principal protein in dairy products, rice protein or soy protein, the mice given casein developed the largest atherosclerotic lesions. (In humans as well as animals, apolipoprotein E plays an important role in cholesterol transport, so a deficiency of this protein increases risk for the development of atherosclerosis.) Mice given rice or soy protein fared much better. In trying to understand why, the researchers evaluated blood levels of nitric oxide. Mice fed either rice or soy protein diets were found to have increased blood levels of L-arginine (the amino acid that the body uses to produce nitric oxide) and nitric oxide metabolites when compared to those given casein-based feed. However, the L-arginine content of the rice and soy diets was not high enough to explain the amount of protective benefit they conferred, so the researchers concluded that these foods must also contain other cardioprotective compounds.

A Good Source of Fiber

The health benefits of brown rice continue with its fiber; a cup of brown rice provides 14.0% of the daily value for fiber, which has been shown to reduce high cholesterol levels, one more way brown rice helps prevent atherosclerosis. Fiber also helps out by keeping blood sugar levels under control, so brown rice is an excellent grain choice for people with diabetes. As we mentioned above, the fiber in brown rice can also help to protect you against colon cancer since fiber binds to cancer-causing chemicals, keeping them away from the cells lining the colon, plus it can help normalize bowel function, reducing constipation.

Fiber from Whole Grains and Fruit Protective against Breast Cancer

When researchers looked at how much fiber 35,972 participants in the UK Women's Cohort Study ate, they found a diet rich in fiber from whole grains, such as brown rice, and fruit offered significant protection against breast cancer for pre-menopausal women. (Cade JE, Burley VJ, et al., International Journal of Epidemiology).

Pre-menopausal women eating the most fiber (>30 grams daily) more than halved their risk of developing breast cancer, enjoying a 52% lower risk of breast cancer compared to women whose diets supplied the least fiber (<20 grams/day).

Fiber supplied by whole grains offered the most protection. Pre-menopausal women eating the most whole grain fiber (at least 13 g/day) had a 41% reduced risk of breast cancer, compared to those with the lowest whole grain fiber intake (4 g or less per day).

Fiber from fruit was also protective. Pre-menopausal women whose diets supplied the most fiber from fruit (at least 6 g/day) had a 29% reduced risk of breast cancer, compared to those with the lowest fruit fiber intake (2 g or less per day).


Read More ~ WHFoods: Brown rice

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