A new trial has found that calcium and vitamin D may decrease levels of abdominal fat in overweight adults.
Abdominal fat is linked with a higher risk of several diseases, including heart disease, hypertension and type 2 diabetes. Reducing excess levels of this type of fat is crucial for those wanting to improve their long-term health.
The trial, published in the American Journal of Clinical Nutrition, was carried out by researchers at Massachusetts General Hospital, in Boston. It tested the effect of fortified orange juice on the fat levels of 171 healthy overweight and obese adults between the ages of 18 and 65.
The research team carried out two double-blind, placebo-controlled trials. One trial tested a regular Calcium and Vitamin D (CaD) fortified orange juice. The second trial tested a reduced calorie (‘lite’) CaD-fortified orange juice. Abdominal fat or ‘visceral adipose tissue’ (VAT) was measured by x-ray before and after the trial.
The trials lasted 16 weeks, during which each participant drank three 240ml glasses of orange juice fortified with 350mg calcium and 100IU vitamin D per day. The control groups drank unfortified regular or unfortified ‘lite’ orange juice.
The results showed that abdominal fat in those drinking the regular fortified orange juice decreased by 12.7cm2 on average. Those who drank the unfortified juice saw a decrease on just 1.3cm2.
In addition, those who drank the fortified ‘lite’ juice saw a decrease in abdominal fat of 13.1cm2, compared with just 6.4cm2 in the unfortified ‘lite’ juice control group.
"Our results suggest that, in overweight and obese adults, a moderate reduction in energy intake and supplementation of calcium and vitamin D in juice beverages lead to a reduction in intraabdominal fat”, concluded the researchers.
Many experts believe that calcium and vitamin D are involved in the healthy metabolism of fat. It is also thought that calcium might accelerate weight loss by binding to fat in the intestine and removing it from the body.
Dr. Angelo Tremblay, of Laval University in Quebec, Canada, has another theory. "Our hypothesis is that the brain can detect the lack of calcium and seeks to compensate by spurring food intake, which obviously works against the goals of any weight loss program".
“A large portion of the population is deficient in vitamin D, and dietary calcium intake often does not meet current recommendations,” the researchers stated.
Whle research is in its early stages, it certainly seems sensible to ensure that you are getting sufficient amounts of these nutrients in your diet, by avoiding denatured, processed foods.
To improve your calcium levels, you should ensure that you are eating plenty of calcium-rich foods, and that you are absorbing the mineral effectively. Rich sources of calcium include dairy, sardines and salmon, leafy greens such as mustard greens, and green vegetables such as broccoli. Calcium absorption also requires adequate dietary magnesium, phosphorus, and vitamin A, C and D.
Supplements can also be helpful in boosting your intake, expecially if you are on a reduced calorie diet. Calcium citrate is believed by many to be the most efficiently absorbed form of calcium, rather than the cheaper carbonate form.
For those supplementing vitamin D, the emulsified form is often considered to be well absorbed.
References Jennifer L Rosenblum, Victor M Castro, Carolyn E Moore, Lee M Kaplan. Calcium and vitamin D supplementation is associated with decreased abdominal visceral adipose tissue in overweight and obese adults. American Journal of Clinical Nutrition. January 2012.