Calcium's role in weight loss

Many studies, in various age groups and ethnicities, have shown the positive effects of calcium on body fat reduction, but the overall relationship is still complex and inconsistent.

A few studies have investigated the role of calcium in low-fat dairy and indicate that it causes dietary fat to be excreted in the faeces.

Although many people are lactose intolerant, they are still able to tolerate cheese, yoghurt and other products made from milk. One study published in the Internal Journal of Obesity (January 2010) shows that with a 30 per cent energy-restricted diet and an increase in either dairy or non-dairy calcium, both lactose tolerant and intolerant people increased their faecal fat excretion over the 12-week trial period. The vitamin D and protein profile of dairy is said to play a positive role in body fat reduction.

Other studies suggest that low-calcium diets lead to increased body fat and an increased desire to consume calories, and that a high-calcium diet will have the opposite effect. All these studies are carried out over short periods and the existing evidence is still controversial. Although weight loss is seen over a short time, there is no evidence to support long-term weight loss and even maintenance. Also, the amount of weight loss in each study is small. In one study the faecal fat loss could theoretically equal to about 0.7 kg fat loss over one year.

Good sources of calcium

The recommended dietary allowance (RDA) for calcium in the Caribbean is 1000mg (with the largest recommendation for pregnant women). Excellent sources of calcium are: yoghurt (eight ounces) provides 415mg, three ounces of sardines with bones provide 324 mg, one-and-a-half ounces of cheddar cheese provide 306mg, eight ounces of non-fat milk provide 302mg, half-cup tofu (made with calcium sulphate) provides 204 mg, calcium-fortified soy drink provides about 500mg.

Not all calcium consumed is absorbed in the intestines. Foods with high levels of oxalic acid such as beans, sweet potato and leafy greens such as spinach can reduce calcium absorption. Foods high in phytic acid such as beans and whole grain products can also affect calcium absorption.

The percentage of calcium absorbed throughout the life cycle varies from about 60 per cent in infancy and childhood to about 20 per cent during adulthood. Therefore, dietary intake should be adequate to ensure absorption at required levels.

Rosalee M. Brown is a registered dietitian/nutritionist who operates Integrated Nutrition and Health Services; email: yourhealth@gleanerjm.com.