Debbie Nicholson

Research reveals low calcium intake puts women at a higher risk for common thyroid condition

Primary hyperparathyroidism or PHPT occurs when calcium levels are too low and the body responds by increasing production of parathyroid hormone, which causes more calcium to be taken from the bone and more calcium to be reabsorbed by the intestines and kidney, resulting in weak bones, fractures and kidney stones. Prior studies have suggested there is an association between untreated PHTP and increased risk of heart attack, stroke and high blood pressure.

View slideshow: Food and Calcium

In the United States, about 100,000 people develop primary hyperparathyroidism each year. he disorder is diagnosed most often in people between age 50 and 60, and women are affected about three times as often as men according to the National Endocrine and Metabolic Diseases Information Service.

Calcium intake is known to influence parathyroid hormone production and therefore may be important in the development of PHPT. However, no study to date has explored this relation in detail over many years.

A team of researchers at Brigham and Women's Hospital set out to examine the association between calcium intake and risk of primary hyperparathyroidism in women in this prospective cohort study.

Researchers followed 58,354 female registered nurses that were enrolled in the Nurses’ Health Study I, aged 39 to 66 years in 1986 and had on history of primary hyperparathyroidism. Their calcium intake from both die t and supplements were evaluated every four years using food frequency questionnaires over a 22-year period.

During the 22 year follow-up there were 277 incident cases of primary hyperparathyroidism.

Women were divided into five groups based on their calcium intake. After adjusting for several factors including age, body mass index and ethnicity, women in the group with the highest intake of dietary calcium had a 44% reduced risk of developing PHPT compared with the group with the lowest intake.

Even the women who were taking a moderate dose at 500mg daily of calcium supplements showed a 59% lower risk of developing PHPT in comparison to women who did not take the supplements. Analyses restricted to participants with regular physical exams did not significantly change the association between calcium intake and risk of primary hyperparathyroidism.

“We report results from the first prospective study of the relation between calcium intake and risk of primary hyperparathyroidism. In women, increased dietary and supplemental calcium intake was associated with a reduced risk for developing primary hyperparathyroidism, independent of age, body size, diet, and other factors,” according to the discussion in the study.

The researchers pointed out “since we conducted an observational study, there could be unknown confounders that we did not control for in our analysis.”

Dr. James Norman, MD,FACS,FACE, Chief of Surgery at the Norman Parathyroid Center in Florida, is recognized as one of world's foremost experts on parathyroid disease remarks that calcium supplements in modest doses "are likely to provide more benefits than risks"… and, over many years, even a moderate increase in calcium concentration probably helps reduce the incidence of parathyroid tumors."

This study is published in the journal BMJ.

According to the Office of Dietary Supplements, National Institute of Health, the amount of calcium you need each day depends on your age. All adults age 19 to 50 need 1,000 mg daily, for women 51 to 70 years 1,200mg daily.

It is recommended that you get the recommended amounts of calcium through your daily dietary intake. If you do not get the required amounts then you may need to take calcium supplements.

The two main forms of calcium dietary supplements are carbonate and citrate. Calcium carbonate is inexpensive, but is absorbed best when taken with food. Some over-the-counter antacid products, such as Tums® and Rolaids®, contain calcium carbonate. Each pill or chew provides 200–400 mg of calcium.

Calcium absorption is best when a person consumes no more than 500 mg at one time. So a person who takes 1,000 mg/day of calcium from supplements, for example, should split the dose rather than take it all at once.

Before starting any supplement check with your physician first.