The Health Benefits of Common Beans

Introduction

Legumes (beans) are among the oldest cultivated plants. In fact, fossil records
demonstrate that prehistoric people domesticated and cultivated legumes for
food. Today, this extremely large category of vegetables contains over 13,000
species and is second only to grains in supplying calories and protein to the
world's population. Compared to grains, legumes supply about the same number of
total calories, but usually provide 2-to-4 times as much protein.
Legumes are often called "the poor people's meat," however, they might be better
known as the "healthy people's meat." Many legumes, especially soybeans, are
demonstrating impressive health benefits. Diets rich in legumes are being used
to lower cholesterol levels, improve blood glucose control in diabetics, and
reduce the risk of many cancers. Legumes contain many important nutrients and
phytochemicals, and when combined with grains, they form a complete protein.
According to studies conducted by the United States Department of Agriculture,
richly colored dried beans offer a high degree of antioxidant protection (see
below). In fact, small red kidney beans rated the highest just ahead of
blueberries.
The soybean, thanks largely to the United States is now the most widely grown
and utilized legume, accounting for well over 50% of the world's total legume
production. In terms of dollar value, the soybean is the United States' most
important crop, ranking above corn, wheat, and cotton.


A Quick Primer on Common Beans

Common beans are variants of Phaseolus vulgaris and include black, kidney, lima,
mung, navy, pinto, and string (or snap) beans. All of the varieties of Phaseolus
vulgaris originated in Peru over 7,000 years ago, and were then spread by
migrating bands of Native Americans into Latin and North America. The early
explorers and settlers of the 15th, 16th, and 17th centuries were introduced to
these beans by the natives. In fact, the basic recipes for Boston baked beans
and succotash were derived from those used by Native Americans. Common beans
were then introduced into Europe in the 15th century by Spanish explorers
returning from their voyages to the New World. They were subsequently spread to
Africa and Asia by Spanish and Portuguese traders.

As common beans are a very inexpensive form of good protein, they have become
popular in many cultures throughout the world. However, their use as a health
promoting food today seems to have been eclipsed by the growing popularity of
soybeans and soy foods. Nonetheless, there is an emerging appreciation on the
benefits of consumption of beans based upon the results of recent scientific
investigations. One of the big differences between the common bean and the
soybean is the absence of phytoestrogens and goitrogens in common beans.

The key nutritional benefits of common beans are quite similar to those
discussed above for soybeans except that they are much lower in fat
content—usually only 1-to-2%. Their protein content and quality is quite similar
though. Common beans also offer an excellent source of complex carbohydrate and
fiber. They are a very good source of folic acid and molybdenum. Common beans
are also a good source of phosphorus, iron, protein, magnesium, manganese, and
potassium.


Health Benefits

The major health benefit of common beans is their rich source of
cholesterol-lowering fiber. In addition to lowering cholesterol, the high fiber
content of beans prevents blood sugar levels from rising too rapidly after a
meal, making these beans an especially good choice for individuals with
diabetes, insulin resistance, or hypoglycemia.

The common beans’ contribution to heart health lies not just in their fiber, but
in the significant amounts of antioxidants, folic acid, vitamin B6, and
magnesium these beans supply. Folic acid and B6 help lower levels of
homocysteine, an amino acid that is an intermediate product in an important
metabolic process called the methylation cycle. Elevated blood levels of
homocysteine are an independent risk factor for heart attack, stroke, or
peripheral vascular disease, and are found in between 20-to-40 percent of
patients with heart disease.

Intake of common beans is also protective against cancer. In one analysis of
dietary data collected by validated food frequency questionnaires in 1991 and
1995 from 90,630 women in the Nurses Health Study II researchers found a
significant reduced frequency of breast cancer in those women who consumed a
higher intake of common beans or lentils. That was not surprising, what was
surprising was that only beans and lentils seemed to offer protection. Intake of
tea, onions, apples, string beans, broccoli, green pepper, or blueberries had
not protective effct. Eating beans or lentils two or more times per week was
associated with a 24% reduced risk of breast cancer.

The largest USDA study of food antioxidants reveals common beans are amoung the
best sources. Researchers with the United States Department of Agriculture
analyzed antioxidant levels in over 100 different foods. Each food was measured
for antioxidant concentration as well as antioxidant capacity per serving size.
Base upon the results, the USDA has provided a list of the top 20 ranking of
foods by antioxidant capacity. Several common beans appear within the list
including small red beans at the top.

USDA Ranking of Foods by Antioxidant Capacity

Ranking Food Item Serving Size Total antioxidant capacity per serving size
1 Small Red Bean (dried) Half cup 13727
2 Wild blueberry 1 cup 13427
3 Red kidney bean (dried) Half cup 13259
4 Pinto bean Half cup 11864
5 Blueberry (cultivated) 1 cup 9019
6 Cranberry 1 cup (whole) 8983
7 Artichoke (cooked) 1 cup (hearts) 7904
8 Blackberry 1 cup 7701
9 Prune Half cup 7291
10 Raspberry 1 cup 6058
11 Strawberry 1 cup 5938
12 Red Delicious apple One 5900
13 Granny Smith apple One 5381
14 Pecan 1 ounce 5095
15 Sweet cherry 1 cup 4873
16 Black plum One 4844
17 Russet potato (cooked) One 4649
18 Black bean (dried) Half cup 4181
19 Plum One 4118
20 Gala apple One 3903

Legumes and Flatulence

One of the problems with legumes is increased intestinal flatulence (gas) or
intestinal discomfort. Most humans pass gas a total of 14 times per day, with a
total of 1 pint. About half of the gas is swallowed air and another 40% is
carbon dioxide given off by bacteria in the intestines. The remaining 10% is a
mixture of hydrogen, methane, sulfur compounds, and by-products of bacteria,
such as indoles, skatoles, ammonia, and hydrogen sulfide. It is this last
fraction that is responsible for the offensive odors.

The flatulence causing compounds in legumes are primarily oligosaccharides,
which are composed of 3-to-5 sugar molecules linked together in such a way that
the body cannot digest or absorb them. Because the body cannot absorb or digest
these oligosaccharides, they pass into the intestines where bacteria break them
down. Gas is produced by the bacteria as they digest the oligosaccharides. Navy
and lima beans are generally the most offensive.

The amount of oligosaccharides in legumes can be significantly reduced by
properly cooking or sprouting them. In other words, the amount of flatulence
produced by legumes can be dramatically reduced by proper cooking. If you still
experience increased flatulence when you eat legumes even if they are cooked
properly, you may wish to try a commercial enzyme preparation such as
MultiEnzyme from Natural Factors or Beano.

Cooking Common Beans

Although most beans can be purchased precooked in cans, cooking your own offers
significant economical, as well as possibly health, benefits. Cooking your own
will produce 3 times the amount compared to canned products.

Dried beans are best prepared by first soaking them overnight in an appropriate
amount of water in the refrigerator to prevent fermentation. Soaking will
usually cut the cooking time dramatically. If soaking overnight is not possible,
here is an alternate method: place the dried legumes in an appropriate amount of
water in a pot, for each cup of dried legumes add 1/4 teaspoon of baking soda,
bring to boil for at least 2 minutes, and then set aside to soak for at least 1
hour. The baking soda will soften the legumes and help breakdown the troublesome
oligosaccharides. The baking soda will also help reduce the amount of cooking
time. Be forewarned, however, beans cooked using the quick soak and no soak
methods may split or develop a slightly mushy consistency. For beans that retain
an even shape, ideal texture, and tender, creamy bite without mushiness,
overnight soaking is the optimal method. Also beans that have not been presoaked
may need some additional water, about ¼ to ½ cup per
cup of beans, to replace the water that evaporates as steam during their longer
cooking process.

Before cooking presoaked beans, regardless of soaking method, skim off any skins
that floated to the surface, drain the soaking liquid, and then rinse them with
clean water. The beans should be brought to a gentle boil and then simmered with
a minimum of stirring to keep them firm and unbroken. A pressure cooker or crock
pot can also be used for convenience. Regardless of cooking method, do not add
any seasonings that are salty or acidic, such as vinegar, wine, tomatoes, or
citrus fruits and their juices, until after the beans have been cooked since
adding them earlier will make the beans tough and greatly increase the cooking
time.
Whenever possible, use the cooking liquid as well as the beans. About 35% of the
B vitamins and 50% of the folic acid will leach into the liquid when beans are
cooked for 1 hour and 15 minutes.

If you are running short on time, you can always use canned beans in your
recipes. If the beans have been packaged with salt or other additives, simply
rinse them after opening the can to remove these unnecessary additions. Canned
beans need to only be heated briefly for hot recipes, while they can be used as
is for salads or prepared cold dishes.

Guide to Cooking Dried Common Beans

Dried Beans (1 cup, dry) Cups Water or Broth Cooking Time (presoaked) Cooking
Time (unsoaked) Cups Yielded
Black Beans 4 1 hr. - 1 1/2 hrs. 2 hrs. 2 1/4
Black-eyed Peas 3 30-45 min. 1 hr. 2
Cannellini (White Kidney Beans) 3 45 min. 1 hr. 2 1/2
Great Northern Beans 3 1/2 1 1/2 hrs. 2 hrs. 2 2/3
Green Split Peas 4 45 min. 1 hr. 2
Yellow Split Peas 4 1 - 1 1/2 hrs. 2 hrs. 2
Peas, whole 6 1 - 2 hrs. 2 hrs. 2
Kidney Beans 3 1 hr. 2 hrs. 2 1/4
Lima Beans, large 4 45 - 1 hr. 1 1/2 – 2 hrs. 2
Lima Beans, small 4 50 - 60 min. 1 1/2 – 2 hrs. 3
Mung Beans 2 1/2 1 hr. 1 ½ hrs. 2
Navy Beans 3 45-60 min. 1 ½ hrs. 2 2/3
Pinto Beans 3 1 - 1/2 hrs. 2 hrs. 2 2/3



Key References:

Messina MJ. Legumes and soybeans: overview of their nutritional profiles and
health effects. Am J Clin Nutr. 1999;70(Suppl.3):439S-450S.
Adebamowo CA, Cho E, Sampson L, et al. Dietary flavonols and flavonol-rich foods
intake and the risk of breast cancer. Int J Cancer 2004;114(4):628-633.
Wu X, Beecher GR, Holden J, et al. Lipophilic and hydrophilic antioxidant
capacities of common foods in the United States. J. Agric Food Chem
2004;52;4026-4037.
McIntosh M, Miller C. A diet containing food rich in soluble and insoluble fiber
improves glycemic control and reduces hyperlipidemia among patients with type 2
diabetes mellitus. Nutr Rev 2001;59(2):52-5.
Menotti A, Kromhout D, Blackburn H, et al. Food intake patterns and 25-year
mortality from coronary heart disease: cross-cultural correlations in the Seven
Countries Study. The Seven Countries Study Research Group. Eur J Epidemiol
1999;15:507-15.