This week’s research review focuses on the folic acid issue.
The first article published in JAMA found that: “Treatment with folic acid plus vitamin B(12) was associated with increased cancer outcomes and all-cause mortality in patients with ischemic heart disease in Norway, where there is no folic acid fortification of foods.”
The second article study published in the journal Nutrition and Cancer found an inverse association between dietary folate intake and prostate cancer risk and primarily risk of high-grade prostate cancer.
The final article brings up the issue of deliquescence, which is defined as “To dissolve and become liquid by absorbing moisture from the air.” Although the article is specific to powders, the press is focusing on pills:
High humidity present in bathrooms and kitchens could be degrading the vitamins and health supplements stored in those rooms, even if the lids are on tight, a Purdue University study shows. (Purdue News, March 2, 2010)
Most bottle vitamins contain a dessicant pack to absorb moisture. Some use cobalt chloride as an indicator because it turns from blue to red in the presence moisture.
Higher quality manufacturers “over-stuff” their vitamins to make certain that the amounts on the label are available throughout the product lifetime.
Cancer incidence and mortality after treatment with folic acid and vitamin B12
(Ebbing, Bonaa et al. 2009) JAMA Download
CONTEXT: Recently, concern has been raised about the safety of folic acid, particularly in relation to cancer risk. OBJECTIVE: To evaluate effects of treatment with B vitamins on cancer outcomes and all-cause mortality in 2 randomized controlled trials. DESIGN, SETTING, AND PARTICIPANTS: Combined analysis and extended follow-up of participants from 2 randomized, double-blind, placebo-controlled clinical trials (Norwegian Vitamin Trial and Western Norway B Vitamin Intervention Trial). A total of 6837 patients with ischemic heart disease were treated with B vitamins or placebo between 1998 and 2005, and were followed up through December 31, 2007. INTERVENTIONS: Oral treatment with folic acid (0.8 mg/d) plus vitamin B(12) (0.4 mg/d) and vitamin B(6) (40 mg/d) (n = 1708); folic acid (0.8 mg/d) plus vitamin B(12) (0.4 mg/d) (n = 1703); vitamin B(6) alone (40 mg/d) (n = 1705); or placebo (n = 1721). MAIN OUTCOME MEASURES: Cancer incidence, cancer mortality, and all-cause mortality. RESULTS: During study treatment, median serum folate concentration increased more than 6-fold among participants given folic acid. After a median 39 months of treatment and an additional 38 months of posttrial observational follow-up, 341 participants (10.0%) who received folic acid plus vitamin B(12) vs 288 participants (8.4%) who did not receive such treatment were diagnosed with cancer (hazard ratio [HR], 1.21; 95% confidence interval [CI], 1.03-1.41; P = .02). A total of 136 (4.0%) who received folic acid plus vitamin B(12) vs 100 (2.9%) who did not receive such treatment died from cancer (HR, 1.38; 95% CI, 1.07-1.79; P = .01). A total of 548 patients (16.1%) who received folic acid plus vitamin B(12) vs 473 (13.8%) who did not receive such treatment died from any cause (HR, 1.18; 95% CI, 1.04-1.33; P = .01). Results were mainly driven by increased lung cancer incidence in participants who received folic acid plus vitamin B(12). Vitamin B(6) treatment was not associated with any significant effects. CONCLUSION: Treatment with folic acid plus vitamin B(12) was associated with increased cancer outcomes and all-cause mortality in patients with ischemic heart disease in Norway, where there is no folic acid fortification of foods. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00671346.
Folate intake and prostate cancer risk: a case-control study
(Shannon, Phoutrides et al. 2009) Download
Folate deficiency has been implicated in the carcinogenesis of several tumor types. The role of folate in prostate cancer remains indeterminate. We investigated folate as a risk factor for prostate cancer among 140 biopsy-confirmed prostate cancer patients, 230 age-matched clinic controls, and 250 negative prostate biopsy controls. Dietary folate intake was inversely associated with overall risk of prostate cancer as compared to clinic controls (P for a linear trend = 0.003). When stratified by disease severity, dietary folate and folate from natural sources were associated with reduced risk of high-grade cancer as compared to both clinic controls (P for a linear trend = 0.0009 and 0.02, respectively) and biopsy negative controls (P for a linear trend = 0.03 and 0.05, respectively). There was no interaction between alcohol consumption and folate intake. These analyses support an inverse association between dietary folate intake and prostate cancer risk and primarily risk of high-grade prostate cancer.
Impact of deliquescence on the chemical stability of vitamins B1, B6, and C in powder blends
(Hiatt, Ferruzzi et al. 2008) Download
Single vitamin ingredients and blends in premixes are widely used in the food and supplement industries and are predominantly in powder form. To meet label claims and/or determine appropriate overages, it is important to characterize the stability of these ingredients. Although moisture is a known promoter of instability in powder blends, the combined effects of storage relative humidity (RH), formulation, and deliquescence on the stability of these systems are not well-characterized. The objective of this study was to determine the effect of deliquescence on the stability of vitamins B 1, B 6, and C and their mixtures. Deliquescence points (RH 0s) for all formulations were determined by moisture sorption analysis. Single, binary, ternary, and quaternary mixtures of thiamin HCl, pyridoxine HCl, sodium ascorbate, and fructose were stored in RH-controlled environmental chambers between 43 and 98% RH at 22 degrees C for up to 12 weeks. Vitamin stability was determined by high-performance liquid chromatography (HPLC). Formulation and storage RH significantly affected vitamin stability. Thiamin and ascorbate degradation were significantly promoted above the RH 0, while pyridoxine was least affected by storage RH. The deliquescence lowering phenomenon enhanced moisture sorption of blends at RHs below the RH 0s. Ascorbate enhanced thiamin degradation. Therefore, formulation, storage conditions, and the relation of these to deliquescence points may affect the shelf life, quality, and functionality of vitamin blends and should be considered in product development, processing, storage, and use.
Ebbing, M., K. H. Bonaa, et al. (2009). "Cancer incidence and mortality after treatment with folic acid and vitamin B12." JAMA 302(19): 2119-26.
Hiatt, A. N., M. G. Ferruzzi, et al. (2008). "Impact of deliquescence on the chemical stability of vitamins B1, B6, and C in powder blends." J Agric Food Chem 56(15): 6471-9.
Shannon, J., E. Phoutrides, et al. (2009). "Folate intake and prostate cancer risk: a case-control study." Nutr Cancer 61(5): 617-28.