Vitamin D Deficiency Decreases Mobility Among Obese

WASHINGTON—Among severely obese people, vitamin D may make the difference between an active and a more sedentary lifestyle, according to a new study published in the Journal of Clinical Endocrinology & Metabolism.

The cross-sectional study examined physical functioning and vitamin D levels in 252 severely obese people. Severe obesity occurs when a person’s body mass index (BMI) exceeds 40. About 6.5% of American adults are severely obese.

Participants were timed as they walked 500 meters and climbed up and down a single step 50 times. They also provided estimates of their physical activity. Researchers took a blood sample to measure each participant’s vitamin D levels. For analysis, the study population was divided into three groups based on vitamin D levels.

The study found severely obese people who also were vitamin D deficient walked slower and were less active overall than their counterparts who had healthy vitamin D levels. The study found the group with the highest vitamin D levels had the fastest walking times and highest amount of self-reported physical activity. This group also had the lowest average BMI of the study participants.

“People with severe obesity already are eight times more likely to have poor physical function than people with a healthy BMI," said Tomás Ahern, M.B., B.Ch., B.A.O., of St. Columcille’s Hospital and St. Vincent’s University Hospital in Dublin, Ireland. “Poor vitamin D status contributes to the deterioration of physical function in this population. Among those with severe obesity, 43% are at risk of vitamin D deficiency."

Vitamin D is one of many vitamins and minerals considered "shortfall" nutrients—nutrients that are typically low in the American diet. Vitamin D acts as a hormone in the body and has important roles in bone health and muscle function.  In fact, studies show vitamin D status may be directly related to muscle functioning and physical performance, while vitamin D deficiency leads to soft bones, as well as muscle weakness.

As demand for convenient, on-the-go meals and snacks increases, consumers are beginning to understand and appreciate the role of functional foods, granting food and beverage manufacturers the opportunity to provide consumers these shortfall nutrients—which also include calcium, magnesium and potassium—in formats like snacks and bars. Or even more simply, many of these nutrients can be found in dairy products; milk and some brands of yogurt are among very few foods that are natural or fortified sources of vitamin D. (Check out the "Dairy Ingredients in Sports Nutrition" Digital Issue from Food Product Design for more on this.)

In terms of weight management, consumers tend to reduce calories by consuming better-for-you (BFY) foods and beverages with reduced fat and sugar content. In fact, BFY reduced-fat and -sugar food and beverage value sales combined amounted to $150 billion globally in 2013, up from $142 billion in 2008. What's more, weight management foods are following the trend for convenient foods by adding functional benefits. For example, fiber and protein are gaining ground in the weight-management space, prompting innovations like protein-enriched breads and cereals, as well as high-fiber bars and even fiber-fortified beverages.

But while food is a large part of the equation, the obesity epidemic will take a multi-factorial effort to address the challenge of the overweight. For a closer look, including consumer trend data, insights on regulatory and legislative challenges in the obesity arena and info on the latest initiatives, check out FPD's The Boardroom Journal's "Thinking Big: Chipping Away at Obesity."