There is also growing evidence for the many health benefits of vegetarian diets, and eating patterns with high consumption of fruits and vegetables have been linked to better bone health outcomes. However, there are concerns about the adequacy of vegan diets for bone health due to the lack of dairy consumption.
Lower BMD has been observed more consistently in vegansBut few prospective studies have examined the effects of vegetarian diets on the risk of fractures.
The objectives of the present study were to examine the association of hip fracture with five diets in non-Hispanic white women and men (aged 45 and older), and to determine whether this association is altered by calcium and vitamin D supplementation.
The Adventist Health Study 2 (AHS-2), a large cohort study funded by the National Cancer Institute to examine the relationships between lifestyle and health outcomes, consists of 96,000 participants in North America recruited between 2002 and 2007. The current study population is limited to peri- and postmenopausal non-Hispanic white women and men aged 45 and over who have completed at least 1 follow-up questionnaire. After all the necessary exclusions, a cohort of 34,542 (18,732 women and 15,810 men) was obtained.
Upon registration, participants completed a comprehensive lifestyle survey, including a validated Food Frequency Questionnaire (FFQ).
Diet reminders were used to group participants into 5 diets: vegan, lacto-ovo-vegetarian (LOV, do not eat meat or fish but eat eggs and dairy products), pesco-vegetarian (do not eat no meat but eat fish, dairy and eggs), semi-vegetarian (eating fish / meat once a week or less) and non-vegetarian (NVEG).
Every two years, participants received follow-up questionnaires in the mail that included the following item: “Have you had any fractures (fractures) of your wrist or hip after 2001?” “
Nutrient intakes, using the Nutrition Data System for Research database, and relevant covariates known to be associated with bone health were compared across the 5 diet continuum.
There were notable differences in lifestyle factors among the diet models. Vegans reported the lowest use of hormone therapy and the highest frequency of walking ≥5 miles / week. LOVs were more likely to have a graduate degree and less likely to have ever smoked. Vegans and LOVs generally had a lower number of comorbidities than the other 3 diets. NVEGs were the least likely to have a graduate degree and the most likely to have smoked or consumed alcohol.
Among vegans, 32% were supplemented with both vitamin D and calcium, compared to ∼ 50% in other diet groups. Magnesium intake was also consistently (22% to 29%) higher in all diets in those who consumed both calcium and vitamin D than in those who took none or only one of the supplements. The average dose of each supplement differed little depending on the choice of diet: ∼ 660 mg of Ca / d and ∼ 13.5 g of vitamin D / d.
Non-supplemented vegans had a dietary vitamin D intake 11.2% lower than supplemented vegans and a dietary vitamin D intake 31% to 53% lower than other food groups.
Intakes of total calcium and total vitamin D were higher in women, largely due to the higher frequency of supplementation.
In men, no association was found between diet and risk of hip fracture in age-adjusted analyzes. Multivariate analysis and stratification on vitamin D and / or calcium supplementation did not change these results. In women, there was a significant association between diet and hip fracture, with a higher proportion of cases among those consuming a plant-based diet. The incidence of hip fracture per 1000 PYRS was 3.9 and 2.4 for vegans and NVEGs, respectively.
Age-adjusted models in the female cohort showed an increased risk of hip fracture from NVEGs to vegans, with vegans having a 53% higher age-adjusted fracture risk than NVEGs.
However, the vegan diet, when supplemented with both calcium and vitamin D, was associated with the same or lower risk of fracture as NVEG or other diet categories. These results therefore suggest that vitamin D and calcium are independently important and necessary for an optimal vegan diet.
The authors point out that the lower risk of fracture in men has been attributed to anatomical and hormonal advantages. In early adulthood, men have higher BMD and larger bones for a given height and weight than women. With aging, greater loss of bone density and greater increase in porosity of cortical bone has been observed in women. In addition, the impact of the drop in testosterone in men has minimal impact on bone loss compared to the drop in female hormones.
They note that the additional use of the two nutrients for fracture prevention purposes is intensely debated, but they argue that their data strengthens the case for supplementation.
“In women, a vegan diet was associated with a significantly higher risk of hip fracture. However, a vegan diet supplemented with both vitamin D and calcium did not lead to a higher risk of fracture. hip than the NVEG diet, ”he added. concludes the report.
“Because the vegans in this study have the lowest number of co-morbidities among the diet models, this would qualify them as healthy adults living in the community. Nonetheless, the very food choices that appear to be associated with low co-morbidities also appear to contribute to a higher risk of hip fracture. Thus, our results confirm the importance of an adequate intake of calcium and vitamin D to prevent hip fractures in women following a vegan diet.
Source: The American Journal of Clinical Nutrition
Thorpe. DL, Beeson. WL, Knutsen. R., Fraser. GE and Knutsen. SF
“Dietary Patterns and Hip Fracture in Adventist Health Study 2: Combined Vitamin D and Calcium Supplementation Alleviates Increased Risk of Hip Fracture in Vegans”