Writing in the journal Nutrients, German scientists suggest a supplement regimen of vitamin B12, vitamin D and iron is more than adequate for runners following a lacto-ovo-vegetarian and vegan diet.
“In our study, all vitamin B12 biomarkers showed an adequate to optimal supply when compared to reference values,” the study says.
“The findings were independent of the respective dietary group but dependent on supplementation.
“Therefore, recreational athletes adopting a vegan diet should be encouraged to take dietary vitamin B12 supplements.”
The merits of a plant-based nutritional approach for athletes is topical in sports medicine with debate about whether this diet can provide all the required nutrients in adequate amounts.
Several nutrition societies in the past have said a well-planned vegetarian dietary pattern, including a wide range of plant foods, can be adequate for athletes.
A number of professional sportspeople from various disciplines are on record as describing the shift to a plant-based diet to improve sporting performance or prolong careers.
Previously, it has been assumed that limiting animal products in the diet increases the risk of certain micronutritional deficiencies.
Animal-derived foods like lean red meat, fish, and eggs are excellent sources of vitamin B12 and provide high amounts of bioavailable zinc, iron, and vitamin D.
Furthermore, dairy products are rich in calcium and other minerals. Consequently, calcium, zinc, iron, vitamin B12, and vitamin D are described as critical nutrients in vegetarian and especially vegan dietary patterns.
The cross-sectional study began comparing the micronutrient status of omnivorous (OMN, sample size (n) - 27), lacto-ovo-vegetarian (LOV, n = 26), and vegan (VEG, n = 28) recreational runners.
The team, from Hannover’s Leibniz University and Hannover Medical School in Germany, also took note of biomarker levels of vitamin B12, folate, vitamin D, and iron.
Serum levels of calcium, magnesium, and zinc were also noted as were lifestyle factors and supplement intake, which was recorded via questionnaires.
Results found approximately 80% of each group showed vitamin B12 adequacy with higher levels found in supplement users.
Mean red blood cell folate exceeded the reference range (over 340 nanomols per lire (nmol/L)) in all three groups.
Furthermore, vitamin D levels were comparable and low prevalence (<20%) of vitamin D inadequacy was found in all three groups.
Further results found less than 30% of each group had depleted iron stores but iron deficiency anaemia was not found in any subject.
Despite their findings, the study adds that vitamin B12 results should be “considered with caution” as previous studies show an inadequate B12 status in the majority of vegans and vegetarians.
With serum 25(OH)D concentrations reflecting the amount of vitamin D attained from both dietary sources and made in the body, this is considered a sensitive biomarker for the vitamin D status.
“Adequate vitamin D supply in the present subjects could be explained by the high proportion of Supplement Users (SU) (specific vitamin D supplements as well as multivitamin supplements),” the study says.
“Interestingly, all subjects who consumed vitamin D (containing) supplements had 25(OH)D levels above 50 nmol/L and, therefore, had an adequate supply, while inadequate to deficient supply concerned only non-SU.
“Overall, in the total study population the vitamin D status was dependent on vitamin D supplement intake.”
Regarding iron levels, the study says supplementation is not crucial for an adequate iron supply adding, “Since the iron bioavailability is higher in animal-based foods compared to plant-based foods a similar status could be only achieved through a high intake of iron-containing plant-based foods such as whole grain and legumes as well as availability-enhancing food ingredients (e.g., vitamin C)”.
The team acknowledge the study’s limitations highlighting the small sample size and age range (18–35 y).
“The study took place mainly in summer months, which possibly influenced study results,” they conclude. “Further, the current training phase could have an effect on the results.”
Published online: doi.org/10.3390/nu11051146
“Micronutrient Status of Recreational Runners with Vegetarian or Non-Vegetarian Dietary Patterns.”
Authors: Josefine Nebl et al