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The Burden of Food-borne Pathogens on Public Health

Folate and Selenium Increase Colon Health

Magnesium Supplements Reduce Hot Flashes in Breast Cancer Patients

Review Finds “Small, but Significant” Support for Calcium in Weight Loss

The Burden of Food-borne Pathogens on Public Health

Food safety became a high-visibility issue in the United States with the signing of the Food Safety Modernization Act on January 4, 2011.

According to estimates from the Center for Disease Control (CDC), 1 in 6 Americans succumbs to illness caused by exposure to food-borne pathogens each year. A recently released report by the University of Florida’s Emerging Pathogens Institute quantifies the occurrence of food-related disease and ranks the top combinations of food and pathogens by frequency.

The report looks at 14 leading pathogens across 12 food categories to uncover the top risks in our food system. The top 5 pathogens identified by the report (campylobacter, Toxoplasma gondii, Listeria monocytogenus, salmonella, and norovirus), account for $12.7 billon in economic loss annually. Breaking out the burden of these pathogens by individual food sources, the 10 most common combinations of food and pathogen drive loss in excess of $8 billion. Disease burden includes the impact of treatment and economic loss related to lost productivity.

The study’s top 10 pathogen/food combinations in terms of annual disease burden are:

1. Camplylobacter (from poultry)
2. Toxoplasma gondii (from pork)
3. Listeria monocytogenus (from deli meats)
4. Salmonella (from poultry)
5. Listeria monocytogenus (from dairy products)
6. Salmonella (from complex foods)
7. Norovirus (from complex foods)
8. Salmonella (from produce)
9. Toxoplasma gondii (from beef)
10. Salmonella (from eggs)

Total disease incidence grouped by food type, however, makes complex foods (predominantly driven by norovirus) the most frequent offender, with cases occurring at a 3 to 1 ratio when compared to the number 2 food-type position, occupied by poultry. Below that, illness from produce (third) occurs at a 1 to 13 rate compared to complex foods, and illness from eggs (fourth) occurs at nearly 1 to 26.

Review the full report at http://www.epi.ufl.edu/sites/www.epi.ufl.edu/files/RankingTheRisksREPORT.pdf

Folate and Selenium Increase Colon Health

A pair of studies on colon health, 1 addressing the effects of folate and the other selenium, were recently published in Clinical Nutrition (published online ahead of print, doi:10.1016/j.clnu.2011.04.007 and the British Journal of Nutrition, (2011 Aug:106:4) respectively.

The folate study, performed in Japan, set out to determine a baseline minimum serum folate concentration that associates with reduced risk of colorectal adenoma. To accomplish this, the authors reviewed the cases of 1510 patients where, following barium enema examination, the patients underwent total colonoscopy for suspected colorectal lesions.

History of alcohol consumption was noted in the preexamination evaluation, as well as serum folate and B12 concentrations. In establishing the folate baseline, researchers excluded from consideration any patient with anemia, history of colonoscopy, over consumption of alcohol, or malignancies. The remaining 258 males and 200 females comprised the 458 eligible patients (aged 40 to 70 years) used for the basal comparison from the original 1510.

The most significant statistical variation was seen in the serum folate level of males, where patients with adenoma exhibited average concentrations of 8.0 ng/mol and those without averaged 9.2 ng/mol (P=.001). Female patients did not differ significantly in serum folate levels (10.7 with adenoma vs. 10.9 without). Overall the study did not find any significant difference in prevalence of adenoma in patients with serum folate concentration above 8 ng/mol, and concludes that folate concentrations above that level are sufficient to define the lowest risk level for adenoma.

In the selenium study, the researchers intended to build upon findings that selenium may have advantages for regulating the risk of certain diseases, such as colorectal cancer. To that end, they studied the effects of selenium-enriched milk protein (dairy-Se) versus selenium-rich yeast (yeast-Se) on plasma selenium levels and rectal selenoprotein gene expression. It was reasoned that, if these genes were not regulated by selenium, there was little potential for using selenium to reduce risk for colorectal cancer.

Over 6 weeks, 23 healthy volunteers with plasma selenium in the lower half of the population range were supplemented with dairy-Se or yeast-Se at 150 mcg/day, followed by a 6-week washout period. Blood samples were collected every 2 weeks and rectal biopsies were obtained at the outset, after supplementation, and after the washout period. Researchers examined plasma selenium levels; glutathione peroxidase (GPx) activity; and rectal messenger ribonucleic acid (mRNA) of selenoprotein P (SeP), cytosolic GPx-1, gastrointestinal GPx-2, and thioredoxin reductase-1 (TrxR-1).

In both groups, plasma selenium levels rapidly increased (P<.001) and plasma GPx did not change significantly. After 6 weeks, both groups also showed an increase over baseline for rectal SeP mRNA (P<0.05). However, dairy displayed some benefits the yeast did not, including: a sustained SeP elevation after the washout period (P<.05), and elevated readings of rectal GPx-1 and GPx-2 mRNA at 6 weeks (P<.05). In conclusion, the study showed that dairy-Se effectively regulated the expression of several rectal selenoproteins relevant to risk for colorectal cancer.

Magnesium Supplements Reduce Hot Flashes in Breast Cancer Patients

A pilot phase II trial at the Virginia Commonwealth University Health System found that frequency and severity of menopausal hot flashes were reduced in 19 of the 25 women who completed the trial, according to the journal Supportive Care in Cancer (2011, 19:6).

In the program, 29 women who experienced at least 14 hot flashes per week were identified for participation. Each was given an oral course of magnesium oxide at 400 mg/day. Dosage escalated to 800 mg/day if needed. A hot flash score (frequency x severity) at baseline was compared to the end of treatment. Side effects caused 4 women to discontinue participation, 2 because of level 1 diarrhea, 1 because of headache, and 1 because of nausea. The dosage was increased during the study for 17 of the women.

Overall, hot-flash frequency was reduced by 41% compared to the baseline (P =.02) and severity was reduced by 50% (P=.04). Of the 25 women, 14 experienced a hot flash score reduction of 50% and adding to this those who experienced less of a reduction, the score for 19 total was reduced at least 25%. According to the women, fatigue, sweating, and distress were all significantly reduced. As a result of these observations, a randomized, placebo-controlled trial is planned.

Review Finds “Small, but Significant” Support for Calcium in Weight Loss

Addressing the proliferation of unproven weight-management claims used in marketing supplements, the authors of a review study at Exeter University in the United Kingdom published in Nutrition Reviews (2011, 69:6) sought to determine whether calcium supplementation positively affected weight loss.

In the systematic review, the authors searched for randomized clinical trials of at least 6 months in duration. No trials were excluded for age, gender, language, or publication date. Eligible trials included 24 studies, but with further review, only 7 of these were included in the authors’ review. Of these, the authors reveal that 5 of the included trials were not of good reporting quality.

Analysis of the 7 studies revealed a “small, but significant” reduction in body weight for calcium (mean difference 0.74 kg with a 95% confidence interval), and in body fat (0.93 kg with a 95% confidence interval) versus placebo.

In conclusion, the authors agree that calcium supplementation offers measurable, statistically significant weight loss for overweight or obese individuals, with the caveat that “the clinical relevance of this finding is uncertain.”