The effect of vitamin B12 on endurance athletes
Over the last century there have been numerous breakthroughs on Vitamin B12 (cobalamin) including; its role in the recovery process of patients suffering from pernicious anaemia through an increased red blood cell count (Minot & Murphy, 1926), how low B12 levels can lead to detrimental effects on health, and that the vitamin cobalamin can be isolated (Scott & Molloy, 2012).
Vitamin B12 is believed to have first been noticed, yet still unidentified, in two unique studies, one by Combes in 1823 and one by Addison in 1858. Here, the authors discovered that patients who were suffering from an anaemia type which caused stomach rotting, this was linked with uniquely large red blood cell types that contained more nuclei, also known as granulocytes. The cause of this abnormal molecular structure was what was creating questions that needed to be answered over the next 25 years (Herbert, 1987). Later, studies found these abnormally sized blood cells to be the result of a reduction in the speed on DNA synthesis within the body (Herbert, 1965; Herbert & Das, 1976) which – when DNA reduction speed was analysed in humans – was found to be caused by the lack of folate available, or, the inability to utilise folate because of low vitamin B-12 levels (Herbert, 1965; Herbert, 1987; Herbert, 1987; Herbert, 1985).
Minot & Murphy (1926) were amongst the first authors to discover that a change in diet by increasing vitamin intake for pernicious anaemia suffering participants can have a beneficial effect on health and improve the symptoms. Pernicious anaemia is the low count of red blood cells (RBC) due to a lack of vitamin B12 (National Heart, Lung, and Blood Institute, 2011). A study took forty five participants suffering from pernicious anaemia and they were given a diet plan to follow from 6 weeks to 2 years, depending on whether they chose to continue with it. The diet was significantly higher in iron and protein with a high level of fruits and vegetables. From using this diet, participants saw health improvements and symptomatic reductions as well as a vast improvement in RBC count. Therefore, vitamin B12 is important to sustain RBC levels as intense exercise has been shown to reduce the number of RBC (Reinhart, 1983). Vitamin B 12 was isolated in the late 1940’s after the discovery of its link with pernicious anaemia (Rickes et al., 1948; Smith, 1948).
The bacteria Lactobacillus lactis Dorner (LLD) was discovered in the mid 1900’s from liver extracts (Shorb, 1947). Shorb (1948) later concluded that this bacteria had a large influence within the liver extracts, and linked this with the high rate of vitamin B12 production within patients suffering from pernicious anaemia who were being treated with liver extracts. Therefore, vitamin B12 affected LLD growth which was a positive, major factor for sufferers of pernicious anemia and their recovery. West (1948) supports this after supplementing a suffering participant with 150 mg (?) with isolated, crystalline B12 and receiving an astounding response by increased growth of different blood cell types and haemoglobin. Much of the research conducted on vitamin B12 seemed to be noticeably between 1990-2000 when researching journals, and ‘Okawa, M.’ was a frequent author in many of the studies. This was because Okawa was involved with many studies in this time period which focused on the effects of vitamin B12 on sleeping disorders and sleeping patterns (Takahashi, 1999; Okawa, 1998; Okawa, 1997; Yamadera, 1996; Uchiyama, 1995; Mishima, 1992; Takahashi, 1992; Okawa, 1991; Okawa, 1990) but testing more general representative group of a population rather than athletes specifically which is what we would like to. Another name which was a frequent occurrence when researching was, ‘Herbert, V’. He graduated from Columbia university in chemistry and went on further to pass medical school and managed to prove that low levels of folic acid led to magaloblastic anaemia but making himself the subject tested on (Oransky, 2003).
Previous research has shown that an athlete who is deficient in any vitamin will perform worse, and these low levels can negatively affect performance (Gravina, 2012). Deficiency in vitamin B12 has been shown to result in developing anaemia and a decreased endurance capacity (Lukaski, 2004), so athletes should consider reviewing their diet and daily energy intake, or consider adding a vitamin supplement into their diet (Woolf, 2006). The first authors to look into the effect of vitamin B12 on athletic performance were Montoye et al. (1955) and Montoye et al. (1954). Both studies were specifically focusing on how supplementing with vitamin B12 can affect performance. Montoye et al. (1955) used a group of adolescent boys that were split into a vitamin, placebo & control group which were administered with supplements 5 days a week for 7 weeks. Results showed there to be no improvements in cardiovascular efficiency but significant improvements in 88 yard sprint speed. The other test conducted by Montoye et al. (1954) was testing to see whether supplementing with vitamin B12 could increase an athlete’s work capacity, but unfortunately access to the article was restricted. Later in 1978, Tin-May-Than et al. (1978) conducted a study where participants, males between 18-21, were given 1mg of cyanocobalamin three times a week over a six week period to see if supplementing with B12 could affect performance capacity, but there was no improvement or decrease in performance.
There have been recent studies which have looked into the use of a preworkout supplement to improve performance including B12. Additionally, there are studies which have tested to see if a general nutritional supplement, containing B-12, affected performance (Vaz, 2011; Spradley et al., 2012). Spradley et al. (2012) tested a pre-workout supplement on twelve cyclists (grass roots level) over a period of 3 weeks, and the participants were requested to not use any nutritional supplements 6 weeks prior. The preworkout supplement contained 85mcg of vitamin B12 (methylcobalain) and additionally, 14mg of vitamin B6. The results concluded that the supplement improved overall concentration which enhanced reaction time performance, and reduced the feelings of fatigue so therefore, improved muscular endurance. This study shows that vitamin B12 could be a contributing factor to improvement in performance, but we are still not sure of the effects when it is isolated.
Bonke & Nickel (1989) found by supplementing marksmen with a considerably large quantity of the B vitaminsincluding vitamin B12, there was a significant improvement in accuracy of shots, so therefore, motor movements. Previous research has shown vitamin B12 to improve overall positive feeling within participants who supplemented with B12 in their diet but weren’t suffering from low levels (Morwood, 1952; O’Brien, 1954; Wilkinson, 1968).
Research has found there to be a link between low levels of B vitamins and a reduction in cognitive function & performance amongst the elderly (Wang et al., 2001; Seshadri et al., 2002; Dufouil, 2003; Ravaglia et al., 2005; Tucker et al., 2005; Kado et al., 2005). Tucker et al. (2005) recruited 321 men who were tested on four unique cognitive tests which assessed the participant’s ability to feedback information and utilise their working memory. Participants plasma levels and dietary intakes were assessed throughout the study. A 3 year follow up was carried out and a significant association was found between B vitamins and spatial copying. It was concluded that maintaining B vitamin and folate levels is important to reduce the risk of cognitive declination.
Based on numerous studies previous, vitamin b12 is essential in the production of healthy red blood cells. Not having enough b12 results in b12 deficiency and potentially anaemia. Anaemia causes the body to produce larger than normal red blood cells. Described as megaloblastic, which do not provide oxygen to cells as efficiently, which would therefore reduce oxygen-carrying capacity of the blood, thereby reducing aerobic performance. Furthermore, studies such as Ellis and Nasser (1973) and Nasser and Wrighton (1970) have observed that people with lower levels of b12 will display more significant changes in b12 levels than individuals with moderate levels. These studies displayed improvements in participants who complained of tiredness, fatigue, and headaches. In addition, b12 contributes to the formation of the myelin sheath which enhances cognitive function by increasing the speed of transmission of an action potential in a neuron and the propagation of a nerve impulse via saltatory conduction (Viatcheslav Wlassoff, 2014)
In theory, as the level of Vitamin b12 increases, so does the production of healthy red blood cells (Tin May Than 1978) Erythrocytes contain an iron-based globular protein called haemoglobin, and given its high affinity for oxygen, is vital for the transport of O2 in the blood in the form of oxyhaemoglobin. Highly saturated Hb allows the blood to carry 65-70 times more oxygen than is normally dissolved in the plasma. Each of the four iron atoms of the haemoglobin molecule can loosely bind one molecule of oxygen, which then diffuses into the muscle cells and binds to myoglobin during aerobic exercise. B12 deficiency, or pernicious anaemia, inhibits oxygen transport. The body’s oxygen transport capacity changes only slightly with a normal variation in Hb content. However, a significant decrease in the iron content of red blood cells – associated with lower b12 levels – reduces an individuals oxygen carrying capacity and correspondingly reduces a persons ability to sustain aerobic exercise.
Our study is based on participants’ aged 18+. It is externally valid in terms of stratifying our samples by age, having a wide range of ages, and the exclusion of anaemic. However, this does present some limitations. Due to a wide range of age in our study there are physiological impairments linear with age. For example, gastric acid produced in the stomach releases b12 from the food you consume; such as meat, eggs, and dairy products. Older adults, particularly those aged 40+, produce less gastric acid and so the volume of b12 in their body will decline, and indicate a disadvantage in terms of red blood cell production and aerobic performance. However, based on the consensus of previous research, those with lower b12 levels will show a more drastic increase of b12 with the onset of supplementation, thereby being a limitation.
Despite the allegations in the textbook of yesteryear that everything to be known about b12 was known, in every year for the successive 25 years there was a new milestone of discovery (Victor, Herbert 1986). Therefore, there is a lot to be discovered regarding vitamin b12.
A further limitation is that red blood cells require folic acid, iron, and vitamin b12 for the production of red blood cells, so increasing b12 may be insufficient to improve aerobic performance.
Research into the impact of vitamin B12 in on endurance athletes shows a wide variety of inconsistencies, despite the fact that it is a physiologically viable concept, there is much research suggesting Vitamin B12 has little to no impact on athletic performance in endurance athletes. Van Der Beek (2012) studied a number of vitamins, concluding they did not have a beneficial impact on endurance runners. Tin-May-Than et al (1978) were the first authors to study the direct effect of vitamin B12 on endurance runners, using 1 milligram of cyanocobalamin 3 times per week they found no significant difference in physical performance capacity between cyanocobalamin injection compared to the placebo group.
Lukaski (2004) suggested that whilst a deficiency in vitamin b12 resulted in anaemia and a reduced capacity for endurance exercise, there was no endurance related benefits to someone with no severe deficiency to supplement extra vitamin b12. This is a view supported in research by Finglas (2000), suggesting that exceeding the quantity of vitamin required by the body, 2.4 mcg daily for adults in the case of vitamin b12 is not of any benefit. This undermines the research conducted by Tin-May-Than (1978) as they used 3mg of vitamin b12 per week.
Anaemia, caused by a deficiency in vitamin b12 has been shown to lower cognitive function and impair cardiovascular health, Lukaski (2004) suggested vitamin B12 aids people with anaemia but not the healthy population.
What has not been answered?
Despite the large amount of research conducted into vitamin B12, little has been applied to a sporting situation, more so there have been very few studies looking at the effect of vitamin B12 on trained endurance athletes. As a result, research needs to be conducted into the effect of vitamin b12 specifically on the impact it has on endurance trained athletes.
Furthermore, studies that have been conducted have used a range of dosages, with no consensus as to an optimal dosage for supplementation. The recommended daily amount of vitamin B12 is 2.4mcg a day. Finglas (2000) suggests increased supplementation of vitamins no benefit, in the study conducted by Tin-May-Than (1978) 3mg per week were used, no significant effects were found, this is the highest dosage used to look at the effect of vitamin B12 on fatigue, as there are no side effects of excess supplementation of vitamin B12, it may be worth increasing the dosage to ensure that are results aren’t a result of insufficient dosage.
The vast majority of research on vitamin B12 has focused largely on anaemic participants, supplementation of vitamin B12 have been shown to have a very positive effect on anaemic participants () with less research conducted on the healthy population, it is impossible to make a conclusive statement as to the effect of vitamin b12 on endurance athletes.
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