Low bone mineral density and bone mineral content are associated with low cobalamin status in adolescents.

BACKGROUND: Cobalamin deficiency is prevalent in vegetarians and has been associated with increased risk of osteoporosis. AIM OF THE STUDY: To examine the association between cobalamin status and bone mineral density in adolescents formerly fed a macrobiotic diet and in their counterparts. METHODS: In this cross-sectional study bone mineral density (BMD) and bone mineral content (BMC) were determined by DEXA in 73 adolescents (9-15 y) who were fed a macrobiotic diet up to the age of 6 years followed by a lacto-(-ovo-) vegetarian or omnivorous diet. Data from 94 adolescents having consumed an omnivorous diet throughout their lives were used as controls. Serum concentrations of cobalamin, methylmalonic acid (MMA) and homocysteine were measured and calcium intake was assessed by questionnaire. Analysis of covariance (MANCOVA) was performed to calculate adjusted means for vitamin B12 and MMA for low and normal BMC and BMD groups. RESULTS: Serum cobalamin concentrations were significantly lower (geometric mean (GM) 246 pmol/L vs. 469 pmol/L) and MMA concentrations were significantly higher (GM 0.27 micromol/L vs. 0.16 micromol/L) in the formerly macrobiotic-fed adolescents compared to their counterparts. In the total study population, after adjusting for height, weight, bone area, percent lean body mass, age, puberty and calcium intake, serum MMA was significantly higher in subjects with a low BMD (p = 0.0003) than in subjects with a normal BMD. Vitamin B12 was significantly lower in the group with low BMD (p = 0.0035) or BMC (p = 0.0038) than in the group with normal BMD or BMC. When analyses were restricted to the group of formerly macrobiotic-fed adolescents, MMA concentration remained higher in the low BMD group compared to the normal BMD group. CONCLUSIONS: In adolescents, signs of an impaired cobalamin status, as judged by elevated concentrations of methylmalonic acid, were associated with low BMD. This was especially true in adolescents fed a macrobiotic diet during the first years of life, where cobalamin deficiency was more prominent.

Intolerance to dietary biogenic amines: a review.

OBJECTIVE: To evaluate the scientific evidence for purported intolerance to dietary biogenic amines. DATA SOURCES: MEDLINE was searched for articles in the English language published between January 1966 and August 2001. The keyword biogenic amin* was combined with hypersens*, allerg*, intoler*, and adverse. Additionally, the keywords histamine, tyramine, and phenylethylamine were combined with headache, migraine, urticaria, oral challenge, and oral provocation. Articles were also selected from references in relevant literature. STUDY SELECTION: Only oral challenge studies in susceptible patients were considered. Studies with positive results (ie, studies in which an effect was reported) were only eligible when a randomized, double-blind, placebo-controlled design was used. Eligible positive result studies were further evaluated according to a number of scientific criteria. Studies with negative results (ie, studies in which no effect was reported) were examined for factors in their design or methods that could be responsible for a false-negative outcome. Results of methodologically weak or flawed studies were considered inconclusive. RESULTS: A total of 13 oral challenge studies (5 with positive results and 8 with negative results) were found. Three of them (all with positive results) were considered ineligible. By further evaluation of the 10 eligible studies, 6 were considered inconclusive. The 4 conclusive studies all reported negative results. One conclusive study showed no relation between biogenic amines in red wine and wine intolerance. Two conclusive studies found no effect of tyramine on migraine. One conclusive study demonstrated no relation between the amount of phenylethylamine in chocolate and headache attacks in individuals with headache. CONCLUSIONS: The current scientific literature shows no relation between the oral ingestion of biogenic amines and food intolerance reactions. There is therefore no scientific basis for dietary recommendations concerning biogenic amines in such patients.

Vitamin B-12 status is associated with bone mineral content and bone mineral density in frail elderly women but not in men.

Subclinical vitamin B-12 deficiency is common in the elderly. Encouraged by early indications, we investigated the plasma vitamin B-12 status in association with bone mineral content (BMC) and bone mineral density (BMD) in frail elderly people. Data of 194 free-living Dutch frail elderly (143 women and 51 men) were available. BMC and BMD were measured by dual energy X-ray analysis. Biochemical analyses were performed on plasma or serum including vitamin B-12, methylmalonic acid, homocysteine, 25-hydroxy vitamin D and parathyroid hormone. Women had higher plasma vitamin B-12 (288 and 238 pmol/L, respectively) and lower plasma homocysteine levels (15.8 and 21.3 micro mol/L, respectively) than men. Of the total explained variance of BMC and BMD in women (46 and 22%, respectively), 1.3-3.1% was explained by plasma vitamin B-12, in addition to weight and height or energy intake. In men, the variance of BMC and BMD was explained by weight, smoking and/or height (total R(2) was 53 and 25%, respectively), but not by plasma vitamin B-12. Osteoporosis occurred more often among women whose vitamin B-12 status was considered marginal or deficient than in women with a normal status, i.e., the prevalence odds ratios (after adjustment for weight, age and calcium intake) (95% confidence intervals) were 4.5 (0.8;24.8) and 6.9 (1.2;39.4), respectively. These results suggest that vitamin B-12 status is associated with bone health in elderly women. Future studies on bone health should take into account a possible role of vitamin B-12 status in different populations.

Influence of processing on total, monoglutamate and polyglutamate folate contents of leeks, cauliflower, and green beans.

Bioavailability of dietary folate might be impaired by the polyglutamate chain to which approximately 70% of dietary folates are bound. This chain must be removed enzymatically in the intestine before folate is absorbed as a monoglutamate. To increase formation of monoglutamate folate in vegetables, the vegetables were subjected to various processing treatments. Treatments included freezing (-18 degrees C, 16 h) and thawing (4 degrees C, 24 h) and hydrostatic high-pressure treatment (200 MPa, 5 min). Both freezing/thawing and high-pressure treatment increased the proportion of folate in the monoglutamate form in leeks, cauliflower, and green beans 2-3-fold. However, loss of total folate after these treatments was >55%. It is concluded that conversion of folate polyglutamate to the monoglutamate form in vegetables is possible by certain processing treatments. Potentially this could lead to vegetables with higher folate bioavailability. However, to prevent folate loss into processing water, processing in a closed system should be applied.