Vitamin B12, Vitamin C and Vitamin D.
Vitamin B12
What is it?
Water soluble vitamin.
What does it do?
Responsible for energy production, muscle repair, red blood cell formation and brain function.
Populations Impacted?
Estimated that up to 80% of plant-based athletes are deficient in B12. Females in this category are more impacted than males. Secondly, age appears to impact B12 status with an increased likelihood of deficiency for those >65 years old.
Deficiency Impact
Red blood cell production will be impacted. Resulting in reduced oxygen delivery. Red blood cell numbers, hematocrit and other blood cell markers could be negatively impacted.
Signs and symptoms would include fatigue, pale/yellow skin, weakness in muscles, weight-loss, irritability/low mood and increased heart rate amongst many others.
Blood Testing
Optimal blood levels of B12 will vary depending on the marker being tested.
Serum B12 500-800 pmol/L
Active B12 (holoTC) 80-140 pmol/L
Best Sources
Liver, beef, sardines, mackerel, salmon, feat, cottage cheese, low sodium Vegemite and B12 fortified foods.
Supplementation
2.4 mcg/day is recommended.
For severe deficiency or faster impact, B12 injections can be supplied by your Doctor when required.
Duration for positive effect
For impact to be seen on blood testing, injections will have an immediate effect. B12 in the form of supplement (pills/spray/capsules) and via food intake will take 6-12 weeks to see a positive impact. A daily dosing regime is recommended for best results.
Vitamin C
What is it?
Water soluble vitamin.
What does it do?
Responsible for immune function, assisting iron status, improving collagen synthesis and energy production.
Populations Impacted?
Estimated that deficiency rates as low as 7% in the United States, Australia and the UK. Comparatively, as high as 73.9% in north India in general population.
Deficiency Impact
Scurvy! Gum and follicular bleeding, This is the extreme.
Lower levels or inadequate levels could negatively impact collagen synthesis and predispose athletes to increased risk of illness. A deficiency or insufficiency would be suspected alongside other nutritional deficiency or insufficiency. This is due to the intake being namely through fruits and vegetables.
Iron absorption and metabolism is negatively impacted. This can lead to iron deficiency.
Blood Testing
Blood levels of Vitamin C will vary depending on the marker being tested.
Serum < 0.3 mg/dL (<11.4 umol/L) indicates deficiency
Serum >0.6 mg/dL indicates sufficient.
Leukocyte vitamin C 0 mg/dL indicative of latent scurvy.
Leukocyte vitamin C 0-7 mg/dL deficiency
Leukocyte vitamin C > 15 mg/dl adequate
Best Sources
C's & B's + KGKS
Citrus & Berries + kale, goji, kiwi,
Supplementation
Maintenance
Daily intake 100mg-200mg day. This can be achieved through food intake. Additional vitamin C supplementation is preferred by some athletes due to increased physical exertion. It is not recommended to take more than an additional 1000mg/day
Illness
Start with 1000mg/day and every day increase by 1000mg/day up to a maximum of 8000mg/day. Cease when signs and symptoms of the illness subside. Do not increase the amount of gastro-intestinal distress occurs. This is often paired with 50-100mg elemental zinc. This is short term supplementation for the purpose of reducing severaity and duration of upper repsoratort tract illness.
Iron Absorption
Consume 100-500mg of vitamin C with iron supplementation (if being prescribed). You can also eat vitamin C containing fruits and foods to get the rquired vitamin C intake.
Duration for positive effect
If you are deficient, the impact will be very immediate.
If you are increasing vitamin C intake for respiratory illness then it will reduce severity and duration of symptoms, The amount it impacts it will vary depending on the athlete along wth the tyepe of virus. As soon as you feel sick, start the dosing regime below.
Vitamin D
What is it?
A fat soluble vitamin that is technically a hormone - not a vitamin per se.
What does it do?
Responsible for calcium homeostasis (bone health) with parathyroid hormone, protein synthesis, immune function and gene expression.
Populations Impacted?
Estimated 30-40% adult population are deficient. This increases for athletes with 56-80% having been found to be deficient. Athletes may require higher amounts of vitamin D due t higher calcium demand from training stresses.
Deficiency Impact
Serum vitamin D < 30 ng/mL is associated with an increased risk of stress fractures,
Increased odds ratio for stress fracture with vitamin D insufficiency.
Equivocal results related to supplementation and improvements in upper and lower body strength. KEY takeaway is that even if supplementation increases levels, if >40ng/mL not achieved then no improvements in strength have been observed.
Low serum vitamin D levels were associated with musculoskeletal injuries
Low serum vitamin D levels are statistically significantly associated with the risk of COVID-19 infection.
Blood Testing
Optimal blood levels of Vitamin D
<10ng/mL = rickets (children), osteomalacia (adults)
<20ng/mL = deficient (Endocrine Society definition)
<39ng/mL = insufficient
40-69ng/mL = sufficient
70ng/mL = optimal athletes
Best Sources
Vitamin D comes in two forms. D2 plant sources. D3 animals and sunlight.
D3 is what will positively impact bone health, protein metabolism, immune function and gene expression.
Sunlight, supplementation and fortified foods will have the biggest impact on your levels.
Sunlight YET this impacted by:
- skin color, amount of time spent in the sun,
- weather conditions, latitude and altitude, season, (>40°N latitude)
- time of day, use of sunscreen, and type of clothing
Supplementation
An intake of 1,000 IU of vitamin D per day can raise blood serum levels by approximately 5 ngml
The Institute of Medicine sets the upper limit (UL) at 4,000 IU per day while the Endocrine Society sets the UL at 10,000 IU/day for adults .
1000-2000IU/day work in healthy adolescents YET not in adult athletes+military in fall/winter in >40N LAT
4000-10000IU/day recommended for athletes who are insufficient or deficient for 8-12 weeks before retesting 25(OH)D levels.
Vitamin K2 150-500 mcg/day could be useful to further improve vitamin D absorption and bone mineral density. This may be important for MENOPAUSAL women.
Vitamin K deficiency, as indicated by high serum levels of undercarboxylated osteocalcin (a relative measure of vitamin K status in bone, but not a biomarker of bone health)
Duration for positive effect
8-12 weeks to see measurable impact with blood testing.
References
Chiang, Chien-ming1; Ismaeel, Ahmed1; Griffis, Rachel B.2; Weems, Suzy1. Effects of Vitamin D Supplementation on Muscle Strength in Athletes: A Systematic Review. Journal of Strength and Conditioning Research
Farrokhyar, F., Sivakumar, G., Savage, K. et al. Effects of Vitamin D Supplementation on Serum 25-Hydroxyvitamin D Concentrations and Physical Performance in Athletes: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Sports Med 47, 2323–2339 (2017).
Ogan D, Pritchett K. Vitamin D and the athlete: Risks, recommendations, and benefits. Nutrients 5: 1856–1868, 2013.
Farrokhyar, F., Tabasinejad, R., Dao, D. et al. Prevalence of Vitamin D Inadequacy in Athletes: A Systematic-Review and Meta-Analysis. Sports Med 45, 365–378 (2015).
Harju, T., Gray, B., Mavroedi, A. et al. Prevalence and novel risk factors for vitamin D insufficiency in elite athletes: systematic review and meta-analysis. Eur J Nutr 61, 3857–3871 (2022).
Kuang, Xiaotong et al. “The combination effect of vitamin K and vitamin D on human bone quality: a meta-analysis of randomized controlled trials.” Food & function vol. 11,4 (2020): 3280-3297. doi:10.1039/c9fo03063h
Huang, Z-B et al. “Does vitamin K2 play a role in the prevention and treatment of osteoporosis for postmenopausal women: a meta-analysis of randomized controlled trials.” Osteoporosis international: a journal established as a result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA vol. 26,3 (2015): 1175-86.
