Calcium is vital for bone health, and may be important for reducing colorectal cancer risk, too, according to a U.S. study.

Researchers at the U.S. National Cancer Institute tracked 293,907 men and 198,903 women and found that those with the highest calcium intake from dairy and other foods and from calcium supplements had the lowest colorectal cancer rates.

Yikyung Park of the NCI, part of the National Institutes of Health, said women in the highest fifth of calcium consumption had a 28 percent lower risk for colorectal cancer compared to those with the lowest fifth of calcium intake.

For men, those in the highest fifth had a 21 percent lower risk for colorectal cancer than those with the lower intake.

The researchers followed the people, who were between 50 and 71 years old, for seven years. The people in the study reported extensively on what they ate and what dietary supplements they took.

"For colorectal cancer, both calcium from diet and from supplements reduced the risk of colorectal cancer," Park, whose findings appear in the journal Archives of Internal Medicine, said in a telephone interview.

Foods with lots of calcium include diary products such as milk and yogurt and leafy green vegetables. Calcium is important in preventing osteoporosis.

The researchers said calcium may reduce abnormal growth in cells in the gastrointestinal tract and may help reduce damage to the mucous membrane in the large intestine.

Two other studies published in the same journal on Monday illustrated possible benefits from B vitamins and vitamin D.

In one study, women who took a combination of vitamins B6 and B12 and folic acid were found to have a 34 percent lower risk of age-related macular degeneration after seven years than women who took a placebo.

William Christen of Brigham and Women's Hospital and Harvard Medical School in Boston and colleagues said the findings offered the strongest evidence yet that folic acid and B vitamin supplements may prevent age-related macular degeneration, a leading cause of vision loss in the elderly.

Another study found that people with the lowest blood vitamin D levels reported getting sick with a cold or the flu much more than those with higher levels.

"The findings of our study support an important role for vitamin D in prevention of common respiratory infections, such as colds and the flu," Dr. Adit Ginde of the University of Colorado Denver, one of the researchers, said in a statement.

"Individuals with common lung diseases, such as asthma or emphysema, may be particularly susceptible to respiratory infections from vitamin D deficiency," Ginde adde

www.reuters.com/article/healthNews/idUSTRE51M7BJ20090223