Supplemental vitamin D is available in 2 distinct forms: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Pharmacopoeias have officially regarded these 2 forms as equivalent and interchangeable, yet this presumption of equivalence is based on studies of rickets prevention in infants conducted 70 y ago. The emergence of 25-hydroxyvitamin D as a measure of vitamin D status provides an objective, quantitative measure of the biological response to vitamin D administration. As a result, vitamin D3 has proven to be the more potent form of vitamin D in all primate species, including humans. Despite an emerging body of evidence suggesting several plausible explanations for the greater bioefficacy of vitamin D3, the form of vitamin D used in major preparations of prescriptions in North America is vitamin D2. The case that vitamin D2 should no longer be considered equivalent to vitamin D3 is based on differences in their efficacy at raising serum 25-hydroxyvitamin D, diminished binding of vitamin D2 metabolites to vitamin D binding protein in plasma, and a nonphysiologic metabolism and shorter shelf life of vitamin D2. Vitamin D2, or ergocalciferol, should not be regarded as a nutrient suitable for supplementation or fortification.
vitamin D2 vs vitamin D3 supplementation efficacy, ergocalciferol cholecalciferol bioefficacy comparison, 25-hydroxyvitamin D serum levels vitamin D supplementation, Vieth vitamin D3 potency superiority, vitamin D binding protein ergocalciferol metabolism, vitamin D2 shorter shelf life nonphysiologic metabolism, cholecalciferol supplementation primate species humans, vitamin D fortification form ergocalciferol critique, serum 25-hydroxyvitamin D biomarker vitamin D status, rickets prevention vitamin D equivalence historical studies
PMID 17023693 17023693 DOI 10.1093/ajcn/84.4.694 10.1093/ajcn/84.4.694
Cite this article
Houghton, L. A., & Vieth, R. (2006). The case against ergocalciferol (vitamin D2) as a vitamin supplement. The American journal of clinical nutrition, 84(4), 694-697. https://doi.org/10.1093/ajcn/84.4.694
Houghton LA, Vieth R. The case against ergocalciferol (vitamin D2) as a vitamin supplement. Am J Clin Nutr. 2006;84(4):694-697. doi:10.1093/ajcn/84.4.694
Houghton, Lisa A., and Reinhold Vieth. "The case against ergocalciferol (vitamin D2) as a vitamin supplement." The American journal of clinical nutrition, vol. 84, no. 4, 2006, pp. 694-697.
Caffeine is the most frequently used psychoactive substance in the United States and >90% of reproductive-age women report some amount of intake daily. Despite biological plausibility, previous studies on caffeine and fecundability report conflicting results. Importantly, prior studies measured caffeine exposure exclusively by self-report, which is subject to measurement error and does not account for factors that influence caffeine metabolism. Our objective was to examine associations between preconception serum caffeine metabolites, caffeinated beverage intake, and fecundability. Participants included 1228 women aged 18-40 y with a history of 1-2 pregnancy losses in the EAGeR (Effects of Aspirin in Gestation and Reproduction) trial. We prospectively evaluated associations of preconception caffeine metabolites (i.e., caffeine, paraxanthine, and theobromine) measured from 1191 serum samples untimed to a specific time of day, self-reported usual caffeinated beverage intakes at baseline, and time-varying cycle-average caffeinated beverage intake, with fecundability. Using Cox proportional hazards models, we estimated fecundability odds ratios (FORs) and 95% CIs according to each metabolite. Follow-up was complete for 89% (n = 1088) of participants. At baseline, 85%, 73%, and 91% of women had detectable serum caffeine, paraxanthine, and theobromine, respectively. A total of 797 women became pregnant during ≤6 cycles of preconception follow-up. After adjusting for potential confounders, neither serum caffeine [tertile (T)3 compared with T1 0.87; 95% CI: 0.71, 1.08], paraxanthine (T3 compared with T1 0.92; 95% CI: 0.75, 1.14), nor theobromine (T3 compared with T1 1.15; 95% CI: 0.95, 1.40) were associated with fecundability. Baseline intake of total caffeinated beverages was not associated with fecundability (>3 compared with 0 0.99; 95% CI: 0.74, 1.34), nor was caffeinated coffee (>2 compared with 0 0.93; 95% CI: 0.45, 1.92) or caffeinated soda (>2 0.92; 95% CI: 0.71, 1.20). Our findings are reassuring that caffeine exposure from usual low to moderate caffeinated beverage intake likely does not influence fecundability.This trial was registered at clinicaltrials.gov as NCT00467363.
Purdue-Smithe AC et al., 2016·The American journal of clinical nutrition
Clinically significant premenstrual syndrome (PMS) affects 15-20% of premenopausal women, substantially reducing quality of life. Women with PMS often are counseled to minimize caffeine intake, although only limited evidence supports this recommendation. We evaluated the association between total caffeine, coffee, and tea intake and the development of PMS in a case-control study nested within the prospective Nurses' Health Study II. All participants were free from PMS at baseline (1991). PMS cases reported a new clinician-made diagnosis of PMS on biennial questionnaires between 1993 and 2005, and then confirmed symptom timing and moderate-to-severe impact and severity of symptoms with the use of a retrospective questionnaire (n = 1234). Controls did not report PMS and confirmed experiencing no symptoms or few mild symptoms with limited personal impact (n = 2426). Caffeine, coffee, and tea intake was measured by food-frequency questionnaires every 4 y, and data on smoking, body weight, and other factors were updated every 2-4 y. Logistic regression was used to evaluate the associations of total caffeine intake and frequency of coffee and tea consumption with PMS. After adjustment for age, smoking, and other factors, total caffeine intake was not associated with PMS. The OR comparing women with the highest (quintile median = 543 mg/d) to the lowest (quintile median = 18 mg/d) caffeine intake was 0.79 (95% CI: 0.61, 1.04; P-trend = 0.31). High caffeinated coffee intake also was not associated with risk of PMS or specific symptoms, including breast tenderness (OR for ≥4 cups/d compared with <1/mo: 0.73; 95% CI: 0.48, 1.12; P-trend = 0.44). Our findings suggest that caffeine intake is not associated with PMS, and that current recommendations for women to reduce caffeine intake may not help prevent the development of PMS.
Clinicians often recommend limiting caffeine intake while attempting to conceive; however, few studies have evaluated the associations between caffeine exposure and menstrual cycle function, and we are aware of no previous studies assessing biological dose via well-timed serum measurements. We assessed the relation between caffeine and its metabolites and reproductive hormones in a healthy premenopausal cohort and evaluated potential effect modification by race. Participants (n = 259) were followed for ≤2 menstrual cycles and provided fasting blood specimens ≤8 times/cycle. Linear mixed models were used to estimate associations between serum caffeine biomarkers and geometric mean reproductive hormones, whereas Poisson regression was used to assess risk of sporadic anovulation. The highest compared with the lowest serum caffeine tertile was associated with lower total testosterone [27.9 ng/dL (95% CI: 26.7, 29.0 ng/dL) compared with 29.1 ng/dL (95% CI: 27.9, 30.3 ng/dL), respectively] and free testosterone [0.178 ng/mL (95% CI: 0.171, 0.185 ng/dL) compared with 0.186 ng/mL (95% CI: 0.179, 0.194 ng/dL), respectively] after adjustment for age, race, percentage of body fat, daily vigorous exercise, perceived stress, depression, dietary factors, and alcohol intake. The highest tertiles compared with the lowest tertiles of caffeine and paraxanthine were also associated with reduced risk of anovulation [adjusted RRs (aRRs): 0.39 (95% CI: 0.18, 0.87) and 0.40 (95% CI: 0.18, 0.87), respectively]. Additional adjustment for self-reported coffee intake did not alter the reproductive hormone findings and only slightly attenuated the results for serum caffeine and paraxanthine and anovulation. Although reductions in the concentrations of total testosterone and free testosterone and decreased risk of anovulation were greatest in Asian women, there was no indication of effect modification by race. Caffeine intake, irrespective of the beverage source, may be associated with reduced testosterone and improved menstrual cycle function in healthy premenopausal women.