November 25, 2008

Greater calcium intake correlated with lower body mass index

The November, 2008 issue of the journal Nutrition published the finding of Brazilian researchers of an association between greater calcium intake and lower body mass index in men and women aged 20 to 59.

Researchers at the University of São Paulo in Brazil evaluated data from 1,459 participants in the Health Survey of the State of São Paolo, which collected health information from residents in four areas of the Brazilian state from 2001 to 2002. Calcium intake was calculated from the responses to participant questionnaires, which obtained information on food consumption, physical activity, height, and demographics.

Forty-three percent of the participants were classified as overweight, of which 13.3 percent were obese. The recommended intake value of 1000 milligrams calcium was exceeded by only 4.7 percent of the subjects. For men, the average intake of the calcium was 410 milligrams per day, and for women, the average was 483 milligrams. A significantly higher incidence of overweight and obesity was found among those whose calcium intake levels were in the lowest half of participants. For those whose intake was less than 398.5 milligrams per day, the risk of being overweight was 24 percent higher than the risk experienced by those whose intake was in the top 25 percent at 593.7 milligrams or more.

Possible mechanisms for calcium include reduced fat formation, stimulation of fat break down, and increased binding of intestinal fatty acids which inhibits their absorption. Previous research has shown that increasing calcium intake from 400 to 1000 milligrams per day for one year is associated with an average weight loss of 4.9 kilograms.

“Considering the insights provided by published studies on the antiobesity effects of calcium intake, together with low dairy consumption and low calcium intake presented by the population evaluated in this study, an important component of obesity has been demonstrated,” the authors conclude. “Further clinical research on the effects of calcium on fat metabolism must be pursued with randomized clinical trials.”

Obesity

The National Institutes of Health (NIH) estimate that more than half the adult population of the United States is overweight [defined as a body mass index (BMI) of 25 to 30]. A significant number of these people are obese (defined as a BMI greater than 30). The obesity epidemic is even beginning to affect children, whose obesity rates have doubled in the past two decades (NIH 2005). And instead of declining, obesity rates are rising, along with the frequency of conditions that are closely associated with obesity, such as type 2 diabetes and metabolic syndrome.

The government's answer to the growing epidemic of obesity has been to recommend more exercise and a balanced diet. While there is no doubt these strategies are important, they also display an incomplete understanding of the biological and hormonal changes that underlie obesity among aging adults. The fact is that as we age, we undergo physiological changes that encourage weight gain. These include hormonal changes and alterations in the way our bodies process nutrients.

Recent advances in dietary science have highlighted the crucial role of insulin in weight gain. Produced in the pancreas, insulin is a critical hormone for the control of blood sugar (glucose). Its job is to transport glucose into cells, where the glucose is burned as fuel. While this process is necessary for life, abnormalities in the insulin-glucose system caused by aging, lack of exercise and poor diet can cause major health problems. In aging, cells become more resistant to the effects of insulin. As cells become increasingly insulin resistant, the body compensates by increasing the number of insulin receptors on cells and secreting more insulin in an attempt to drive more blood sugar into muscle and liver cells (Fulop 2003).

Insulin resistance is a dangerous condition. Research suggests that adipose tissue (fat) is a source of pro-inflammatory chemicals that have a role in the development of insulin resistance (Sharma AM et al 2005). Insulin resistance is associated with obesity (in particular, abdominal obesity) (Greenfield JR et al. 2004). It is also associated with aging muscle (Nair KS 2005), physical inactivity, and genetics.

This increase in insulin (called hyperinsulinemia) and decreased insulin sensitivity have a number of harmful effects, including contributing to diseases associated with being overweight (Zeman et al 2005; Garveyet al 1998)

Life Extension Update

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For longer life,

Dayna Dye
Editor, Life Extension Update
ddye@lifeextension.com
954 766 8433 extension 7716
www.lifeextension.com