Adults older than 50 years: Older adults do not absorb naturally occurring vitamin B12 very well. Adults over 50 should get the recommended amount of vitamin B12 from fortified foods or a supplement.
Vegetarians: Vegetarian diets, in particular vegan diets, need to be planned carefully to meet vitamin B12 needs. To estimate the amount of vitamin B12 in your diet, keep a food record for one or two days. Indeed, the Academy of Nutrition and Dietetics AND have recommended that a range of plant-based proteins should be consumed by vegetarians in order to meet their protein and amino acid requirements [ 47 ].
Further, the once-popular recommendation of combining protein sources to achieve a complete essential amino acid profile in each feeding is no longer considered necessary [ 14 ]. Foods such as grains, legumes, nuts and seeds should be included in the vegan diet to ensure that all EAAs are present, and that adequate BCAA are consumed to support recovery and adaptation from training. Examples of high-protein vegan-friendly foods can be found in Table 2. Supplemental protein might be of interest to vegan athletes, particularly if achieving sufficient protein via wholefoods is either difficult or inconvenient.
Emerging data is beginning to support the efficacy of plant-based-protein powders at improving recovery from training [ 48 ] and fostering muscle hypertrophy as part of a resistance training program [ 45 ].
Recent evidence also suggests like-for-like responses when comparing supplemental plant and dairy proteins on body composition and exercise performance as part of a training programme [ 48 ], contrasting previously-reported data [ 45 ].
In comparison to dairy-based protein supplements however, plant-based supplements appear to be much less researched at this time, and further research is needed to understand the effects of individual rice, pea, hemp, etc. The digestibility of plant-based protein appears to be markedly less than that of animal products, which might need to be accounted for when designing a vegan diet [ 50 ].
The PDCAAS has been criticised for disregarding anti-nutrient factors that affect protein absorption, and for truncating protein sources that score in excess of its 1. The DIAAS does neither, and is perhaps a superior system for rating protein digestibility [ 41 , 51 ].
Both systems however indicate that animal-derived proteins score higher than plant-based sources [ 51 ]. However, when factoring in anti-nutrient factors such as phytic acid and trypsin inhibitors, which limit the absorption of nutrients, whey protein isolate appears to be superior to soy protein when using the DIAAS 1. Other important plant-based protein sources such as rice, peas and hemp all score markedly lower than animal-based sources such as eggs, chicken and beef using either system [ 41 , 51 , 52 ].
Indeed, it has been suggested that vegetarians might need to consume more protein than meat eaters to compensate for the poorer digestibility of plant-based sources [ 50 ]. Values of up to 1. In some instances, values of up to 1. Vegan diets tend to be higher in carbohydrates, fibre, fruits, vegetables, antioxidants and phytochemicals than omnivorous diets [ 53 ].
The consumption of micronutrient and phytochemical-rich foods is an important benefit of any plant-based diet [ 3 , 9 ]. This might help to mitigate the effects of excess inflammation and promote recovery from training, although this has yet to be confirmed empirically [ 10 , 12 ].
It has been suggested that some endurance athletes might intentionally adopt a vegan diet in order to meet their carbohydrate needs, or to assist weight management goals [ 10 , 11 , 54 ]. Achieving an adequate carbohydrate intake via a vegan diet is relatively straightforward, and grains, legumes, beans, tubers, root vegetables and fruits can all be consumed to meet carbohydrate requirements satisfactorily. In order to achieve sufficient protein via the consumption of whole foods as recommended in this article, it is recommended that vegans consume beans, pulses, lentils and grains daily—foods that are also abundant in carbohydrate.
However, recall that these foodstuffs are rich sources of fibre. Fibrous, non-digestible carbohydrates and lignin provide volume and bulk, are resistant to digestion and absorption, and promote early satiation and enhance prolonged satiety signalling [ 47 , 56 , 57 ]. For athletes requiring higher energy intakes, the consumption of fibre-rich foods to achieve protein and carbohydrate adequacy might prove to be difficult for some. Due to the lectins in foods such as beans, grains, nuts and potatoes [ 58 ], as well as the fermentation of resistant starch and indigestible carbohydrates found in oats, peas, beans, fruits, and in certain vegetables and lentils , a high-fibre diet can also promote gastric distress in some cases [ 38 , 59 , 60 ].
In order to achieve sufficient carbohydrate for the athletes involved in high-volume training phases it might be appropriate in some contexts to choose some lower-fibre foods when developing high-carbohydrate meals, as long as sufficient micronutrient status particularly B vitamins can be ensured. Foods such as rice, pasta, noodles and buckwheat contain less fibre than oats, lentils, beans and wholegrain breads, and removing the skin from tubers and root vegetables reduces the fibre contents of these foods whilst maintaining decent carbohydrate levels.
The optimisation of carbohydrate consumption with respect to training and competition has been debated in the literature [ 61 ]. Conventional wisdom suggests that maintaining high muscle glycogen stores achieved via a carbohydrate-rich diet , consuming carbohydrates before and during exercise scaled to absolute intensity and mode of exercise , consuming multiple-transportable carbohydrates such as a glucose-fructose mixture , and carbohydrate mouth rinsing to delay fatigue might enhance performance during middle-distance and endurance events [ 37 , 62 ].
In most cases, carbohydrate supplements appear to be vegan-friendly, and so their consumption is feasible for most vegan athletes. Consuming calcium-fortified fruit juices as a liquid carbohydrate might serve dual purposes however, and enable vegans to meet both carbohydrate and calcium needs whilst concomitantly offering possible ergogenic advantages if used as indicated in the literature [ 61 ].
Vegan diets are typically lower in total and saturated fat and higher in n -6 fats than omnivorous and vegetarian diets [ 8 , 13 , 63 ]. This trend appears to be associated with reductions in heart disease, hypertension, type II diabetes, cholesterol and cancer [ 63 ], and is a purported health benefit of veganism.
However, the role of fat in the diet is an area of much discussion, and deleterious effects of fat consumption are not universally accepted [ 64 — 66 ]. Indeed, in some cases, high-fat diets have even been promoted [ 55 ]. Interestingly, research has indicated that low-fat dieting might negatively influence testosterone levels in males [ 67 ].
This might be of interest to athletes needing to maximise anabolism and adaptation to resistance training. However, despite reporting lower total and saturated fat intakes, evidence has also suggested that vegan males do not have statistically lower androgen levels than omnivores [ 68 ]. Relationships between fat consumption, hormones and sport performance might require additional investigation. In many instances, it appears that the health implications of a dietary fat might reflect its fatty acid composition [ 64 , 69 ], meaning that attention should be paid to the quantity and quality of fat consumed.
Achieving recommended values of 0. Due to an absence of marine-sourced fats, vegans appear to consume fewer n -3 fatty acids and possess lower serum n -3 fatty acid levels than omnivores and other vegetarians [ 8 , 13 , 63 , 70 ].
This might have important health and performance implications. The n -3 fatty acids are important for normal growth and development, and appear to play an important role in cardiovascular health [ 71 ], in inflammatory and chronic disease [ 72 ], and might improve exercise-induced bronchoconstriction EIB and immunity [ 73 ]. Of interest to athletes, n- 3 fats might also increase nitric oxide production [ 71 , 74 ], and improve heart-rate variability [ 75 ]. Both n -6 and n -3 fatty acids are parent fatty acids for eicosanoids prostaglandins, thromboxanes and leukotrienes , and n -3 fatty acids appear to possess anti-inflammatory, antithrombotic, antiarrhythmic; hypolipidemic, vasodilatory and antiproliferative properties [ 71 , 72 ].
Both n -6 and n -3 fatty acids are essential, however the long chain n -3 fatty acids eicosapentaenoic acid EPA and docosahexaenoic acid DHA are considered to be under-consumed in the modern western diet in general [ 72 ], and in vegans in particular [ 47 , 70 ]. Elsewhere, Sanders [ 79 ] and Philips [ 14 ] recommend that vegetarian diets limit linoleic acid consumption an n- 6 fatty acid , found in sunflower, corn and safflower oils, for similar purposes.
Roughly 0. While humans do convert a small amount of ALA to DHA, the primary source of this in the diet is cold water fish and seafood.
EPA and DHA exert many of the reported health and performance benefits of n -3 fatty acid consumption and is now a popular supplement [ 80 ]. However, recommendations for vegan-friendly DHA supplements do not appear in the literature at this time [ 9 ]. Recommendations do appear for other food sources of the n -3 ALA, such as flax seeds, walnuts, and chia seeds [ 9 , 14 ]. Achieving micronutrient sufficiency is an important concern for all athletes. The AND have indicated that attention should be paid to achieving adequacy in vitamin B12, iron, zinc, calcium, iodine and vitamin D intakes when designing a vegan diet in particular [ 47 ].
Poorly designed diets might predispose individuals to deficiency regardless of predilection, which could have detrimental health and performance implications [ 2 , 9 , 12 ]. This needs to be understood by those seeking to adopt veganism, and strategies to mitigate the risks of under-consuming these nutrients need to be present if a vegan diet is to optimize health and performance.
Table 3 compares the nutritional implications of several diets omnivorous, pesco-vegetarian, vegetarian and vegan , and provides recommendations for athletes and practitioners. The following section will identify and elaborate upon concerns highlighted in the literature, based upon research indicating what micronutrients might be under-consumed in a vegan diet [ 2 — 4 , 8 , 14 , 47 , 63 , 70 , 87 ].
Due to an absence of animal and dairy products, vegans are at an increased risk of developing Vitamin B12 cobalamin deficiency [ 87 ]. Cobalamin is synthesised from anaerobic microorganisms, in the rumen of cattle and sheep, and humans typically consume pre-formed cobalamin from animal products, which are the main source of B12 in the diet [ 88 ].
Plant-based sources of cobalamin are unusual, unless the plant has been contaminated by manure or from animal waste [ 47 , 88 ]. Cobalamin is essential for normal nervous system function, homocysteine metabolism and DNA synthesis [ 88 ].
Insufficient cobalamin can lead to morphological changes to the blood cells and the development of haematological and neurological symptoms, such as megaloblastic anaemia and neuropathy [ 89 ]. Long-term cobalamin deficiency can lead to irreversible neurological damage, and data indicates that veganism can lead to deficiency if cobalamin is not supplemented [ 14 ].
Sources of vitamin B12 suitable for a vegan diet include Bfortified breakfast cereals and nutritional yeast, as well as dietary supplements. Supplemental vitamin B12 products typically contain cyanocobalamin, although other forms such as methylcobalamin and hydroxocobalamin are available—the latter by prescription only.
Because of this poor bioavailability, sublingual drops, lozenges and transdermal products have been developed and marketed under the pretence that they offer better absorption, however research supporting these claims could not be found when writing this article. Where adequate B12 status cannot be achieved via oral supplementation and fortified food products alone, vegans might need to have serum levels monitored by a medical practitioner if deficiency is suspected [ 87 ]; subcutaneous or intramuscular injections might even be indicated in some contexts [ 87 ]; monitoring B12 status carefully might be necessary for some vegan athletes.
The iron status of vegetarians and vegans has received attention in the literature [ 92 — 94 ], and it appears that owing to a diet rich in whole-grains and legumes, both vegetarians and vegans consume similar amounts of iron as omnivores [ 9 , 63 ]. However, issues with the bioavailability of plant-based iron might mean that vegans need to pay attention to ensuring that sufficiency is prioritized [ 92 , 93 ].
The main source of iron in the vegan diet is found in the non-haem form, which is less bioavailable than the haem iron found in animal products [ 93 ].
Vegan diets also commonly contain dietary inhibitors such as the polyphenols tannin found in coffee, tea, and cocoa and phytates found in whole grains and legumes , which reduce the amount of iron absorbed from the diet. Research into the iron status of vegans has found that female vegans appear to have lower iron stores than omnivores, and are more prone to iron-deficiency anaemia [ 63 , 94 , 95 ].
Male vegans appear to have a similar iron status as non-vegans and are less impacted by iron status [ 63 ]. Iron-deficiency anaemia is caused by insufficient consumption of iron or insufficient absorption of iron and is a decrease in red blood cells RBCs or haemoglobin, leading to symptoms such as tiredness and fatigue; weakness, shortness of breath and reduced exercise tolerance [ 95 ].
Iron deficiency without anaemia has also been shown to reduce endurance capacity, increase energy expenditure and impair adaptation to endurance exercise in females experiencing tissue depletion [ 96 ].
Supplementation has been shown to correct such problems and might be warranted if adequacy cannot be achieved via the diet Indeed, achieving an iron-sufficient diet appears to be rudimentary for all female athletes [ 95 — 97 ].
Interestingly, however, it has been suggested that the body can regulate iron absorption based upon blood concentrations of the mineral [ 14 ]. Low iron status can lead to intestinal adaptations that increase absorption and reduce secretion in order to maintain equilibrium [ 14 ]—an effect that appears to be present with other important micronutrients discussed in this article [ 3 , 97 ]. It appears that humans can adapt to a wide range of iron statuses and intakes, and vegetarians and vegans generally do not appear to suffer adverse health effects because of reduced iron absorption [ 98 ].
Elevated intakes of iron for vegetarians and vegans have been refuted however on the basis that high iron intakes might increase susceptibility to heart disease and cancer [ 99 ], and that supplemental iron might affect the bioavailability of other minerals and copper [ 14 ].
Indeed, it has also been suggested that such recommendations have exaggerated requirements by basing recommendations off of acute feeding studies, where the effects of iron inhibitors and enhancers might have been artificially pronounced [ 3 , 92 , ]. Non-haem iron absorption can be enhanced as well as inhibited , and consuming non-haem iron-rich foods in conjunction with vitamin C appears to increase absorption [ 9 , 92 ].
In cases of where individuals might be prone to iron deficiency, i. A list of food sources for iron and other nutrients discussed in this article can be found in Table 4. Zinc is a constituent of enzymes involved in metabolic processes that relate to DNA stabilisation and gene expression, and is important in cell growth, repair and protein metabolism [ 92 ].
Similar to iron, zinc is widely available in plant-based foods but is also not readily absorbed [ 93 ]. Similarly as well, the body appears to adapt to lower intakes of zinc by reducing losses and increasing absorption in order to maintain equilibrium [ 3 , 97 ]. It has been suggested therefore that vegetarians do not need to pay special attention to consuming this mineral [ 3 ].
However, processing foods can reduce phytate too. Leavening bread activates phytase, breaking down phytic acid, and soaking, fermenting and sprouting nuts and grains can all reduce phytate levels and increase nutrient bioavailability [ ]. Zinc bioavailability appears to be enhanced by dietary protein and inhibited by supplemental folic acid, iron, calcium, copper and magnesium, but might not be affected by the whole-food sources of these nutrients [ ].
If this is not achievable, a supplement should be considered. Owing to issues concerning bioavailability, zinc supplements should not be consumed at the same time as supplemental forms of the aforementioned minerals. Calcium is abundant in a wide range of foodstuffs, most notably dairy products. Data indicates that vegans consume less calcium than omnivores and other vegetarians [ 63 ]. Vegans have been shown to be at a higher risk of fracture due to lower calcium intakes [ ].
Low intakes of calcium are particularly problematic for children and teenagers, where higher calcium requirements are required for bone development [ 78 , ]. As with other minerals, the body appears to be able to regulate calcium status during periods of low consumption. When habitual calcium intakes are low, and when sufficient vitamin D is present, an increased proportion of calcium is absorbed from food [ ]. It has been suggested that lower protein intakes typical of a vegan diet might contribute to greater calcium retention due to high-protein diets promoting calcium excretion in the urine [ , ].
However, evidence demonstrates that protein-rich diets have no effect on calcium retention [ ], and in some instances work synergistically with calcium to improve calcium retention and bone metabolism [ 34 , ].
It is widely recommended that adequate calcium is necessary for blood clotting, nerve transmission, muscle stimulation, vitamin D metabolism and maintaining bone structure [ ]. Indeed, the importance of calcium for the vegan athlete reflects its role in the maintenance of skeletal health during weight-bearing exercise, and increased calcium losses experienced during heavy perspiration [ ]. Calcium requirements might also be exacerbated during phases of calorie restriction, amenorrhea and in some instances of the female athlete triad [ ].
Broccoli, bok choy and kale are particularly high in calcium; green vegetables such as spinach and arugula contain oxalate however, which impedes calcium absorption [ ]. Vegans therefore should choose plant sources that contain low oxalate levels when designing calcium-rich meals.
Vegans can also consume calcium-set tofu, which is also rich in protein, to help achieve their requirements if palatable. If a vegan diet cannot achieve sufficient calcium levels, then a supplement might also be required [ 14 ].
Iodine is an essential trace element needed for physical and mental growth and development, and plays in an important role in thyroid function and metabolism [ 92 ].
Excessively high or low intakes of iodine can lead to thyroid dysfunction, and vegans have been shown to consume both excessively high and low intakes depending on their dietary choices [ , ].
Lightowler and Davies [ ] however found that some vegans consumed excess iodine from seaweed in their study. Iodine content in foods vary according to the soil-iodine content when growing produce , the farming methods used during production, the season it is grown in, and the species of fish if non vegan [ ]. Goitrogens, found in cruciferous vegetables such as cabbage, cauliflower and rutabaga decrease iodine utilisation and might affect adversely thyroid function if consumed in large amounts [ ].
However, cooking such foods appears to destroy many of the goitrogenic compounds present, making this effect unlikely.
Raw-food vegans should look to limit the consumption of raw, goitrogenic foods where possible. Seaweed and sea vegetables are a concentrated source of iodine that are vegan-friendly. Excessively high iodine intakes have been reported in vegans who regularly consume seaweed however [ , ], and in some cases have led to elevated Thyroid Stimulating Hormone TSH levels [ , ]. Elevated TSH might reflect iodine-induced hyperthyroidism or iodine-induced hypothyroidism [ ].
Iodine concentrations in seaweed can vary markedly [ ], and the British Dietetic Association suggests that seaweed might not be a reliable iodine source [ ]. Vitamin D is a fat-soluble vitamin produced in the skin, is essential for calcium absorption and bone health, and plays an important role in many physiological processes [ ]. While humans synthesize vitamin D from exposure to sunlight, vitamin D can also be found in animal products and fortified foods [ ]. Dietary intakes of vitamin D appear to be low in vegans who do not achieve sufficient sun exposure [ ].
Cholecalciferol D3 is an animal-derived version of vitamin D that is now widely available as a supplement [ ]. Ergocalciferol [D2] is a vegan-friendly version of vitamin D but appears to be less bioavailable than cholecalciferol [ , ].
Recently, however, vegan-friendly versions of cholecalciferol derived from lichen, a composite fungal-algae organism, have become commercially available, offering vegans a more bioavailable supplemental option.
These supplements appear to be dosed similarly to animal-derived products, with dosages of — IU per serving being common, and can be used as a like-for-like equivalent for animal-based counterparts. U is supplemented by individuals who do not achieve adequate sun exposure [ ].
Of interest to athletes, Cannell et al. Indeed, Moran et al. Optimising vitamin D status is perhaps an important consideration for all athletes, regardless of dietary choice [ ]. In order to determine vitamin D status, plasma 25OHD levels can be sampled. Further research is warranted to determine optimal vitamin D doses for athletes.
Research indicates that vegetarian and vegan diets reduce muscle creatine stores [ — ]. Creatine is a nitrogeneous, organic acid synthesized endogenously from arginine, glycine and methionine [ ]. Foods such as meat, fish and poultry are rich sources of creatine but are excluded from a vegan diet. Creatine supplementation might also lead to increased plasma volume, improved glycogen storage, improved ventilatory threshold, and reduce oxygen consumption during submaximal exercise [ ].
Interestingly, data indicates that creatine supplementation might be most beneficial for athletes with low pre-existing muscle creatine stores. To highlight, Burke et al. Creatine supplementation might therefore be an important ergogenic aid for vegan athletes to consider, and compensate for reduced muscle creatine stores experienced as a result of their lifestyle choices.
The co-ingestion of creatine with protein and carbohydrate might increase creatine retention by way of insulin-mediated storage, but appears not to have any noticeable performance-enhancing effects beyond stand-alone ingestion [ ].
Similar to muscle creatine levels, evidence also indicates that vegetarians have lower levels of muscle carnosine compared to omnivores [ , ]. Further research is necessary to validate this hypothesis however. Taurine is a sulphur-containing amino acid that appears to play a role in many important physiological processes in humans, including bile acid conjugation, cardiovascular function, neurotransmission and euglycemia, and is obtained from seafood, meat and dairy products [ , ].
Vegans have been shown to consume negligible amounts of taurine [ ], which is conditionally essential in some clinical contexts [ ]. It has been suggested that vegans might benefit from taurine supplements owing to its absence in the vegan diet [ 10 ]. However, further support for this recommendation could not be found in the literature located for this article.
The primary limitation of this review is the lack of research into veganism in sport. To mitigate this issue, information was gathered for this review from multiple sources, and inferences were made from the available data and via reasoned judgements. As such, many of the recommendations in this article require authentication, and so this article should serve as a catalyst for future research as well as a guidance document for athletes and practitioners.
The main strength of this review is its comprehensiveness. In general, vegan diets tend to be lower in Calories, protein, fat, vitamin B12, n -3 fats, calcium and iodine than omnivorous diets, whilst concurrently being higher in carbohydrates, fibre, micronutrients, phytochemicals and antioxidants. Achieving a high energy intake is difficult in some instances, owing to plant-based foods promoting satiety.
Issues with the digestibility and absorption of nutrients such as protein, calcium, iron and zinc might be an issue too, meaning that athletes might need to consume higher amounts of these foods compared to omnivores and other vegetarians. However, through the strategic selection and management of food choices, and with special attention being paid to the achievement of energy, macro and micronutrient recommendations, along with appropriate supplementation, a vegan diet can achieve the needs of most athletes satisfactorily.
For some, a vegan diet is the manifestation of important ethical beliefs, and requires diligence to sustain [ 5 — 7 ]. DR is the sole author for this manuscript, and conceptualised, wrote and edited the article. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
National Center for Biotechnology Information , U. J Int Soc Sports Nutr. Published online Sep David Rogerson. Author information Article notes Copyright and License information Disclaimer. David Rogerson, Email: ku. Corresponding author. Received Apr 4; Accepted Sep 3. This article has been cited by other articles in PMC. Abstract With the growth of social media as a platform to share information, veganism is becoming more visible, and could be becoming more accepted in sports and in the health and fitness industry.
Keywords: Vegan, Vegetarian, Plant-based, Diet. Background Vegan diets might be becoming more visible, owing to the proliferation of social media as a means to share information, experiences and discuss opinions [ 1 ]. Main Text The information in this narrative has been extrapolated from a broad range of academic disciplines, such as the epidemiological and health sciences, in addition to sports nutrition literature.
Energy For most athletes, a well-constructed diet omnivorous or otherwise should provide sufficient energy in order to achieve energy balance [ 15 ]. Table 1 Vegetarian Diets: Definitions. Open in a separate window. Table 2 High Protein Foods. Food Protein per g a Pumpkin seeds dried, uncooked Due to delivery carrier delays, delivery timelines may be a few days longer than expected. Need some help? If none of these options work for you then scroll down and check the links in our footer Brand: NOW.
NOW Nutritional Yeast delivers the natural nutrient profile found in genuine whole foods. This product is sold by weight not volume. Natural color variation may occur in this product. Store in a cool, dry place after opening. Calories 40 Total Fat 0. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
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