Oats, in one form or another, are a staple of most bodybuilders’ diets. Yet few bodybuilders’or anyone else for that matter’ever consider why oat-based foods are so useful. Most of the good publicity about oats is due to their ability to lower blood cholesterol levels. In fact, in 1997 they were the first food recognized as a ‘functional food’ by the United States Food and Drug Administration. Functional foods have properties that foster good health and prevent disease. As a result of all the publicity, oat intake has increased by more than 100 percent in the past 30 years. Oats are a true whole-grain food. Processing them involves removing the outer hull and leaving the inner whole-grain portion, which is known as the groat. The groat is lightly steamed to produce a toasted flavor and inactivate enzymes called lipases that promote rancidity. After that, the groat is sliced and rolled flat.
Cooking times for oat products depend on how thick the oats are. Thus, old-fashioned oatmeal is cut thicker than oatmeal flakes, while instant oatmeal flakes are the thinnest of all and cook the most rapidly. Whole-grain oat products include rolled oats, oatmeal, oat flakes and oat flour. The outer 50 percent of the groat is known as oat bran.
Oats are a treasure trove of nutrients. They’re richer in protein and most nutrients than other whole grains, such as wheat, corn, barley and rye. Oats are the richest whole-grain source of tocotrienols, members of the vitamin E family that may have more potent antioxidant effects than alpha tocopherol, the most common supplemental form of vitamin E. Oats also contain other natural antioxidants, such as polyphenols, saponins and a group of antioxidants unique to oats called avenanthramides. In a study presented at the 2002 Experimental Biology meeting, those special oat antioxidants were found to significantly suppress inflammatory and atherogenic processes that lead to cardiovascular disease.
Dietary fiber exists in two basic forms: soluble and insoluble. Soluble fiber is considered more beneficial in lowering blood fats. It does that in two ways. The first involves a binding of bile acids in the gut, leading to their excretion. That causes the liver to produce more bile acids, a process that requires cholesterol. That, in turn, lowers blood cholesterol levels. The other way that soluble fiber lowers blood cholesterol involves the production in the intestine of short-chain fatty acids, which are then recirculated to the liver, where they may inhibit excess cholesterol synthesis. Oat fiber consists of 55 percent soluble fiber and 45 percent insoluble fiber. Insoluble fiber is vital because it prevents a variety of diseases, including colon cancer, hemorrhoids, constipation, diverticulosis and anal fissures. The soluble fiber in oats consists mainly of beta-glucan, which itself is an interesting compound. Besides being the primary soluble fiber in oats, it also may offer anti-inflammatory effects by activating cytokines, which are chemicals that activate immune cells.
As noted, the most familiar health effect of oats is the lowering of blood fats. That includes lowering total-cholesterol levels as well as low-density-lipoprotein cholesterol levels. LDL is often called bad cholesterol, as it’s linked to cardiovascular disease. The blood lipid effect is most apparent in people who have elevated levels. Studies show that you need to eat 1 1/2 cups of cooked oatmeal, which contains three grams of beta-glucan, to get the lipid-lowering effect. Oats may also elevate high-density lipoprotein, a.k.a. the good cholesterol.
While beta-glucan provides about 75 percent of oats’ lipid-reduction action, other elements contribute to the effect. For example, oats have a specific ratio of the amino acids arginine and lysine that helps lower blood lipids. Soy-based foods also contain the correct ratio of aminos. Other elements in oats that play a role include tocotrienols, which some studies show may cause a regression of arterial plaque. In addition, oats contain monounsaturated fats, which are considered a key player in the positive effects of the so-called Mediterranean diet, which appears to prevent cardiovascular disease and cancer.
An ongoing study of nurses found that eating cold cereals at least five times a week led to a 19 percent lower risk of cardiovascular disease.1 Subjects who ate oatmeal five times a week or more had a 29 percent reduced risk of cardiovascular disease. A study of men showed that eating a high-soluble-fiber diet was more important in preventing cardiovascular disease than eating a lowfat diet.
Another way oats may prevent cardiovascular disease involves a different risk factor: high blood pressure.2 In one study people with high blood pressure ate either 137 grams of oat cereal, containing 12 grams of total fiber (six grams soluble fiber) or wheat cereal containing three grams of fiber daily.3 Of the 45 subjects, 73 percent were able to reduce their blood pressure medication. After 12 weeks average total-cholesterol levels dropped 15 percent, while LDL dropped 16 percent. Blood glucose levels also improved significantly. In the wheat group 42 percent were able to lower their doses of blood pressure medication but showed no changes in blood lipids.
Still another protective mechanism of oats involves the endothelium, or lining of blood vessels. The effects of eating a high-fat meal on the endothelial lining lead to artery constriction; however, one study showed that eating oats and taking 800 units of vitamin E prevented that problem.4
Oats appear to help prevent cardiovascular disease, but what can they do for your workouts and overall nutrition program? The soluble fiber in oats delays carbohydrate absorption. That means if you eat oats with a high-glycemic-index food that would normally cause considerable insulin release, it lowers the glycemic index of the meal, leading to less insulin release. That means more stable blood glucose levels and more sustained energy. Less insulin release also means less bodyfat synthesis, since insulin is the most potent hormonal stimulator of fat.
One study showed that in a 50-gram portion of carbohydrate, each gram of beta-glucan from oats reduced the glycemic index by four units.5 Another found that fiber intake predicted insulin levels, weight gain and cardiovascular risk factors more potently than saturated-fat intake and that eating high-fiber foods helps to prevent obesity by lowering insulin levels. ALL Protein is known to provide a potent satiety effect. Simply put, eating protein helps to reduce appetite, and oats are higher in protein than other grains, such as wheat, barley, corn or rice. The high fiber content of oats also helps to make you feel full, making it easier to diet as well as counteracting the appetite-stimulating effects of insulin. Studies show that people who eat oatmeal or other oat products for breakfast feel more satisfied and eat less for lunch, thus making it easier to lose weight.
Eating oats before training is also helpful. One study compared eating oat, wheat and corn cereals before engaging in exercise. The oats produced less carbohydrate oxidation, along with lower insulin levels, than the other cereals.6 The net effect was less of a drop in glucose levels before exercise due to the blunted insulin release, which would translate into greater energy and more intense workouts.
One problem with exercise is that you use more oxygen when you exercise, which leads to a greater production of oxygen metabolic by-products called free radicals. Among other things, free radicals are associated with muscle inflammation, and they delay recovery following exercise. Even so, a rat-based study showed that when the rodents ate oats before engaging in treadmill running, the oxidative effects of the exercise were significantly lowered.
Oats are also rich in glutamine, an amino acid that helps bolster beneficial immune responses following exercise. Glutamine is vital for the health of the intestinal lining, which uses it as a fuel source. What’s more, the short-chain fatty acids produced from oats also help preserve and protect gastrointestinal function.
Besides these established benefits, some other, not-so-well-documented good effects have appeared in the medical literature. One report indicated that eating green oats helped to wean opium addicts off the drug. Another showed that smokers who ate oats were able to cut down on that dangerous addiction’although a follow-up study failed to confirm those results.
Green oats, often sold under the botanical name of Avena sativa, are often suggested as a sexual enhancer and even appear in a few food supplements marketed for that purpose. In an unpublished study sponsored by the Institute for the Advanced Study of Human Sexuality in San Francisco, 20 men and 20 women, aged 22 to 64, were given a 300-milligram capsule of Avena sativa three days a week for six weeks. Twenty-two percent of the men and 15 percent of the women reported an increase in genital sensation. In addition, 36 percent of the men and 29 percent of the women claimed an increase in orgasm frequency.
The suggested mechanism here is that green oats may lower sex-hormone-binding globulin in the blood. SHBG is produced in the liver and binds to testosterone; however, only the 2 percent of unbound testosterone is considered active. So anything that frees testosterone could have a considerable effect on sexuality. Thus far, however, that effect of oats is strictly anecdotal, since it has never been replicated in any study published in a recognized scientific journal.
Even if oats don’t prove to offer aphrodisiac effects, their other qualities are more than enough to mandate that you include them in any bodybuilding-nutrition plan you use.
1 Wolk, A., et al. (1999). Long-term intake of dietary fiber and decreased risk of coronary heart disease among women. JAMA. 281:1998-2004.
2 Keenan, J.M., et al. (1997). Oat cereal and hypertension. Can J Cardiol. 13(suppl):91B.
3 Pins, J.J., et al. (2002). Do whole-grain oat cereals reduce the need for antihypertensive medications and improve blood pressure control? J Family Pract. 51:353-359.
4 Katz, D., et al. (2001). Acute effect of oats and vitamin E on endothelial responses to ingested fat. Am J Prevent Med. 20:124-129.
5 Jenkins, A.L., et al. (2002). Depression of the glycemic index by high levels of beta-glucan fiber in two functional foods tested in type-2 diabetics. Eur J Clin Nutr. 56:622-628.
6 Paul, G., et al. (1996). Oat, wheat or corn cereal ingestion before exercise alters metabolism in humans. J Nutr. 126:1372-1381. IM