Fortify Bread to Boost Vitamin D and Calcium Intake

Newswise — The latest research shows that vitamin D is more important for bone health than was previously believed. A new study by the University of Maryland's Center for Food, Nutrition and Agriculture Policy (CFNAP) found that both men and women over 55 don't get enough vitamin D, reflecting a June 21 National Public Radio report that experts think many Americans don't get enough vitamin D. Nutrition experts predict that vitamin D will be a hot topic for the next Dietary Guidelines Advisory Committee, to begin its review of the data in 2008 in preparation for the 2010 Dietary Guidelines for Americans.

A recent CFNAP study also shows that Americans, especially adolescent and African American women, don't consume enough calcium at the time they most need it to develop bone density. Here, nutritionist and CFNAP director Maureen Storey talks about the results of the vitamin D study, which also examined the potential of fortifying bread and other grain products to raise calcium and vitamin D intake in low consumption groups. Storey and CFNAP deputy director and director of research Rich Forshee will discuss the topic in detail at next week's Institute for Food Technologists Annual Meeting in Orlando, FL.

Key findings of CFNAP Vitamin D and Calcium Fortification Study- Older men and women don't get the recommended amount of vitamin D - Females, particularly adolescents and young women don't consume enough calcium.- Fortifying multi-grain and whole wheat breads with calcium and vitamin D increases overall consumption by a small amount, but among those who do consume multi-grain and whole wheat bread there is about a 10% increase in vitamin D consumption.- Fortifying a broader range of grain products may have a larger impact.

What role do calcium and vitamin D play in bone development and density?

Storey: Calcium is used throughout the body, and adequate calcium consumption is necessary to maintain bone density. Vitamin D greatly increases the body's ability to absorb and use calcium.

What happens when we don't get enough of either of these nutrients?

Storey: The greatest health risk associated with a lack of calcium and vitamin D is osteoporosis, a disease characterized by fragile bones that are more susceptible to fractures. Osteoporosis is actually a pediatric disease that manifests in old age. Wrist, hip or spinal fractures are the most common symptoms of the disease among older individuals suffering from osteoporosis. The good news is that the risk of osteoporosis and these kinds of fractures can be greatly reduced if adolescents and young adults consume adequate amounts of calcium and vitamin D and get plenty of physical activity, particularly weight-bearing exercise. This is especially important for adolescent and young adult women.

What are the most common dietary sources of calcium and vitamin D?

Storey: Dairy products—like milk, yogurt, and cheese—are the biggest dietary sources of calcium. Other foods, including green leafy vegetables, also contain some calcium. An increasing number of food products are also fortified with additional calcium. Very few unfortified foods contain vitamin D. Milk and other dairy products are fortified with vitamin D, and these foods are currently the biggest source of vitamin D in the diet. Many other foods could be fortified with vitamin D.The human body also produces vitamin D when skin is exposed to sunlight. However, recent studies have shown that many people are not producing enough vitamin D through sun exposure, particularly among people who live in northern climates, use a lot of sunscreen, or have dark skin. Overexposure to sunlight also increases the risk of skin cancer, so it's important to find dietary sources of vitamin D to supplement our natural production of this important vitamin.

Why did your study focus on whole grain bread?

Storey: Breads and grain products are good vehicles for fortification with important but under-consumed nutrients. Breads and grain products are widely consumed, and many vitamins and minerals can be safely added to them. For example, breads and grains are shelf-stable and the added vitamins and minerals are distributed relatively evenly throughout the product. Breads are a cost-effective way to deliver fortified vitamins and minerals for consumers in all income categories. The most recent Dietary Guidelines for Americans encouraged consumers to "make half your grains whole," so we thought it was important to study the impact that fortification of this segment of the bread market could have.

What did your study find?

Several sub-populations fall short of the recommended consumption of vitamin D and/or calcium. Older men and women are unlikely to consume enough vitamin D and females, particularly adolescents and young women, are unlikely to consume enough calcium. We found that fortification of whole grain breads has a small impact on overall calcium and vitamin D consumption, but among those who do consume whole grain breads the fortification leads to about a 10% increase in vitamin D consumption. Broader fortification of grain products with calcium and vitamin D may have a larger impact.

Can't we just take vitamin and mineral supplements?

Storey: People should strive for a healthy overall diet and lifestyle, including lots of physical activity. Dietary supplements are not a replacement for a healthy diet because there are interactions between and among nutrients that we are only beginning to understand. However, both supplements and fortification can play an important role in addressing shortfall nutrients, such as calcium and vitamin D. Carefully targeted fortification plans have a long history of addressing important public health problems. Iodine fortification in salt practically eliminated goiter, and folic acid fortification of grains dramatically reduced neural tube defects in infants. Fortification can be an effective and cost-efficient means to address important nutrient deficiencies. Dietary supplements can also play an important role, particularly when the deficiency is concentrated within a particular segment of the population.

Can you get too much calcium or vitamin D?

Storey: Yes, but it's unlikely anyone would exceed the recommended upper limits in a typical diet or by taking the recommended dose of the common multi-vitamin/mineral supplements. Individuals taking high doses of dietary supplements containing calcium or vitamin D should carefully check the dosage against the recommended limits and consult with their doctor. Any fortification plans should carefully assess the possibility of over-consumption.

What are some of the calcium and vitamin D topics that need further research?

Storey: We need further research on current consumption levels as new data become available. Additional products are likely to be fortified with calcium and vitamin D, and we need to monitor how this affects consumption levels. We also need to do more research on the best fortification strategies and the impact they have on groups of particular concern.

In addition, recent studies have suggested that there may be additional health benefits of vitamin D consumption beyond bone health. These potential benefits deserve further study.

The next round of dietary guidelines is likely to review the recommended upper limit of consumption for vitamin D. Many scientists think the current upper limits are set too low, and this topic is producing a lively and important scientific and policy discussion. We need additional careful analysis of vitamin D toxicity, and we need to develop appropriate risk management strategies to minimize these risks.

Maureen Storey, PhD is a research professor and Director of CFNAP. She also is currently Interim Director of the Joint Institute for Food Safety and Applied Nutrition (JIFSAN), a joint center of the University of Maryland and the U.S. Food and Drug Administration.

The CFNAP vitamin D study was co-authored by Richard Forshee, Ph.D. and Patricia Anderson, MPP, CFNAP faculty members. They used data from the National Health and Nutrition Examination survey to analyze current consumption of calcium and vitamin D from foods and supplements. The study was supported by the Sara Lee Bakery Group.

Forshee, along with Connie Weaver, head of the department of foods & nutrition at Purdue University and member of the 2005 U.S. Dietary Guidelines Advisory Committee, and Julie Jones, professor of nutrition at the College of St. Catherine, will join Storey in the IFT presentation, "Maintaining healthy bones through fortification of whole grain breads with calcium and vitamin D," at the IFT meeting, Sunday, June 25, 2:30 p.m.