Archives for October 2011

Additives meant to protect vitamin C actually cause more harm

Anti-caking agents in powdered products may hasten degradation of vitamin C instead of doing what they are supposed to do: protect the nutrient from moisture.

Lisa Mauer, a Purdue University professor of food science; Lynne Taylor, a professor of industrial and physical pharmacy; and graduate student Rebecca Lipasek study deliquescence, a reaction in which humidity causes a crystalline solid to dissolve. They wanted to understand how anti-cakingagents protect substances such as vitamin C from humidity.

In Mauer’s laboratory, different anti-caking agents were blended with powdered sodium ascorbate, a common form of vitamin C, and were exposed to different relative humidities. Normally, sodium ascorbate deliquesces, or dissolves, at 86 percent relative humidity and is stable below that level. Some anti-caking agents, however, caused the degradation to begin at lower humidity levels.

“The additives that the food industry puts in to make these powders more stable didn’t help the vitamin C, and in some cases actually made things worse,” Lipasek said.

Once vitamin C changes chemically, it no longer holds its nutritional value.

The findings suggest that foods made with powdered vitamin C may lose the vitamin’s nutrients at a lower humidity than once thought. The team’s findings were published in the current issue of the Journal of Food Science.

A variety of anti-caking agents were studied.

“Some of the agents act like little raincoats, covering the particles and protecting them from moisture. Others will absorb the water themselves, keeping it away from the vitamin C particles,” Mauer said. “I really thought some of those anti-caking agents would help, but they didn’t.”

The problem, according to the research, is the chemical properties of the anti-caking agents themselves.

The water-repellent agents, which act like raincoats, are mobile, Lipasek said. When they move around, they clump together and leave some of the vitamin C uncovered. When that happens, moisture is able to reach and degrade the exposed vitamin C.

The moisture-absorbing agents, which absorb the water at a lower humidity than vitamin C, may be absorbing so much moisture that they become saturated. When that occurs, Mauer said, the pH level around the vitamin C can change, or water can move and interact with the vitamin C. Both of these scenarios could lead to further reactions that lower the humidity at which vitamin C deliquesces and changes from solid to liquid. Once the vitamin C dissolves, it is unstable.

Next, Mauer and Lipasek plan to test more complex blends that contain more ingredients along with vitamin C. They also plan to determine how much water is necessary to destabilize vitamin C and how temperature affects the destabilization of vitamin C with anti-caking agents.

The U.S. Department of Agriculture and the Purdue Faculty Scholars Program funded the research.

 

Reference

Lipasek RA, Taylor LS, Mauer LJ. Effects of Anticaking Agents and Relative Humidity on the Physical and Chemical Stability of Powdered Vitamin C. Journal of Food Science, 2011; 76 (7): C1062-C1074.

 

Vitamin D Deficiency Common in Cancer Patients

Predicts advanced disease

More than three-quarters of cancer patients have insufficient levels of vitamin D (25-hydroxy-vitamin D) and the lowest levels are associated with more advanced cancer, according to a study presented on October 2, 2011, at the 53rd Annual Meeting of the American Society for Radiation Oncology (ASTRO).

“Until recently, studies have not investigated whether vitamin D has an impact on the prognosis or course of cancer. Researchers are just starting to examine how vitamin D may impact specific features of cancer, such as the stage or extent of tumor spread, prognosis, recurrence or relapse of disease, and even sub-types of cancer,” Thomas Churilla, lead author of the study and a medical student at the Commonwealth Medical College, Scranton, Pa., said.

Researchers sought to determine the vitamin D levels of patients at Northeast Radiation Oncology Center in Dunmore, Pa., a community oncology practice, and to see if vitamin D levels were related to any specific aspects of cancer. The study involved 160 patients with a median age of 64 years and a 1:1 ratio of men to women. The five most common primary diagnoses were breast, prostate, lung, thyroid and colorectal cancer. A total of 77 percent of patients had vitamin D concentrations either deficient (less than 20 ng/mL) or sub-optimal (20-30 ng/mL). The median serum vitamin D level was 23.5 ng/mL. Regardless of the age or sex of the patient, levels of vitamin D were below the median predicted for advanced stage disease in the patient group.

Patients who were found to be vitamin D deficient were administered replacement therapy, increasing serum D levels by an average of 14.9 ng/mL. Investigators will be analyzing if vitamin D supplementation had an impact on aspects of treatment or survival in the long-term.

“The benefits of vitamin D outside of improving bone health are controversial, yet there are various levels of evidence to support that vitamin D has a role in either the prevention or the prediction of outcome of cancer,” Churilla said. “Further study is needed to continue to understand the relationship between vitamin D and cancer.”