Chicken is rated as a very good source of protein, providing 67.6% of the daily value for protein in 4 ounces. The structure of humans and animals is built on protein. We derive our amino acids from animal and plant sources of protein, then rearrange the nitrogen to make the pattern of amino acids we require.
A Very Good Source of Protein
People who are meat eaters, but are looking for ways to reduce the amount of fat in their meals, can try eating more chicken. The leanest part of the chicken is the chicken breast, which has less than half the fat of a trimmed Choice grade T-bone steak. The fat in chicken is also less saturated than beef fat. However, eating the chicken with the skin doubles the amount of fat and saturated fat in the food. For this reason, chicken is best skinned before cooking.
Protein Protects Against Bone Loss in Older People
Studies show that some sections of the population, especially older people, have poor protein intake. But protein may be important in reducing bone loss in older people. In one study, the 70- to 90-year-old men and women with the highest protein intakes lost significantly less bone over a four-year period than those who consumed less protein. Animal protein, as well as overall protein intake, was associated with preserving bone.
With data from 615 participants in the Framingham (MA) Osteoporosis Study, researchers examined the relationship between protein intakes in 1988-1989 and changes in bone mineral density four years later. They accounted for all factors known to increase risk of bone loss.
Participants who reported the lowest daily protein intakes - roughly equivalent to half a chicken breast - had lost significantly more bone in the hip and spine four years later than those with the highest intakes - equivalent to about 9 ounces of steak and 1 cup of tuna salad. The group with the next lowest intake - equivalent to about 2 cups of cottage cheese - also lost significantly more bone than the highest protein intake group, but only at the hip.
Chicken's Cancer-Protective Nutrients
Chicken is a very good source of the cancer-protective B vitamin, niacin. Components of DNA require niacin, and a deficiency of niacin (as well as other B-complex vitamins) has been directly linked to genetic (DNA) damage. A four-ounce serving of chicken provides 72.0% of the daily value for niacin.
Chicken is also a good source of the trace mineral, selenium. Selenium is of fundamental importance to human health. It 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 have 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 may be the most 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. Four ounces of chicken supply 40.0% of the daily value for selenium.
Protect against Alzheimer's and Age-related Cognitive Decline
Research published in the August 2004 issue of the Journal of Neurology, Neurosurgery and Psychiatry indicates regular consumption of niacin-rich foods like chicken provides protection against Alzheimer's disease and age-related cognitive decline.
Researchers from the Chicago Health and Aging Project interviewed 3,718 Chicago residents aged 65 or older about their diet, then tested their cognitive abilities over the following six years. Those getting the most niacin from foods (22 mg per day) were 70% less likely to have developed Alzheimer's disease than those consuming the least (about 13 mg daily), and their rate of age-related cognitive decline was significantly less. (August 23, 2004)
B vitamins for Energy
Chicken is not only a very good source of niacin, but is also a good source of vitamin B6]. This particular mix of B-complex vitamins makes chicken a helpful food in supporting energy metabolism throughout the body, because these B vitamins are involved as cofactors that help enzymes throughout the body guide metabolic reactions.
Both of these B vitamins are important for energy production. In addition to its DNA actions, niacin is essential for the conversion of the body's proteins, fats, and carbohydrates into usable energy. Niacin helps optimize blood sugar regulation via its actions as a component of a molecule called glucose tolerance factor, which optimizes insulin activity. Vitamin B6 is essential for the body's processing of carbohydrate (sugar and starch), especially the breakdown of glycogen, the form in which sugar is stored in muscle cells and to a lesser extent in our liver. A four-ounce serving of chicken supplies 72.0% of the daily value for niacin and 32.0% of the DV for vitamin B6.
Vitamin B6 for Cardiovascular Health
In addition to its role in energy metabolism, vitamin B6 plays a pivotal role as a methyl donor in the basic cellular process ofmethylation, through which methyl groups are transferred from one molecule to another, resulting in the formation of a wide variety of very important active molecules. When levels of B6 are inadequate, the availability of methyl groups is also lessened. One result of the lack of methyl groups is that molecules that would normally be quickly changed into other types of molecules not only do not change, but accumulate. One such molecule, homocysteine, is so damaging to blood vessel walls that high levels are considered a significant risk factor for cardiovascular disease. As noted above, 4 ounces of chicken will supply about one-third (32.0%) of a person's daily needs for vitamin B6.
