If you look around you, numerous foods are fortified with B-vitamins. It’s common practice for people to reach for a B-complex when they want some additional energy. The discovery of the MTHFR mutation, its relationship to the B-vitamins, and its impact on health has become prominent in many mainstream media outlets. But how much do you really know about this group of essential vitamins?
Let’s review some of the key facts. There are eight vitamins included in the B-vitamin group:
– B1 – Thiamine
– B2 – Riboflavin
– B3 – Niacin
– B5 – Pantothenic Acid
– B6 – Pyridoxine
– B7 – Biotin
– B9 – Folate
– B12 – Cyanocobalamin
Although each one has its individual role, B-vitamins have inter-connecting roles in the body and play important roles as coenzymes, so they’re often discussed together. As coenzymes, these vitamins are involved in essential cellular functions for creating energy and constructing or transforming bioactive molecules.
Below are the symptoms of deficiencies and risk factors:
|Vitamin||Symptoms of Deficiency||Risk Factors for Deficiencies|
|B1||In the early stages: fatigue and weakness, gastrointestinal problems, confusion, memory loss, irritability, emotional problems, issues with sleeping.
In the later stages: Beri-beri, a disease causing cardiovascular dysfunction and nerve damage in the periphery. Symptoms include impaired perception, pain, weakness, shortness of breath, swelling, irregular heartbeat, and heart failure, as well as Wernicke-Korsakoff syndrome, amnesia, ataxia, and abnormal motor function
|Obesity and alcohol abuse|
|B2||Itching or burning in the eyes, pain and tenderness in the mouth, weakness, anemia, fatigue, brain dysfunction, and dermatitis||Genetic predisposition to malabsorption or poor utilization of riboflavin|
|B3||Pellagra: symptoms include diarrhea, depression and anxiety, memory loss, psychosis, muscle weakness, dermatitis, and twitching in the extremities||Alcohol abuse|
|B5||Dermatitis, numbness or burning in the extremities, diarrhea||None|
|B6||Cognitive decline, dementia, irritability, anemia||Oral contraceptives, malabsorption in the elderly, alcohol abuse|
|B7||Depression, seizures, hallucinations, eczema, tingling or burning, and lethargy||Type 2 diabetes and poor glucose regulation|
|B9||Changes in behavior, Alzheimer’s disease, dementia, psychosis, megaloblastic anemia, metabolic abnormalities, lesions in the spinal cord, peripheral neuropathy||Low levels of B2 and B12, MTHFR polymorphism|
|B12||Changes in behavior, Alzheimer’s disease, dementia, psychosis, megaloblastic anemia, metabolic abnormalities, lesions in the spinal cord, peripheral neuropathy||Vegan or vegetarian diet, genetic polymorphisms, malabsorption in the elderly|
As you can see, the B-vitamins have a variety of impacts on your health both alone and combined. Let’s take a quick look at some of the recent studies reviewing the relationship between B-vitamin levels and disease.
It is important for pregnant women and infants to have adequate levels of B-vitamins since they play a key role in brain development. A lot of focus has been spent on ensuring adequate levels of folate to reduce the risk of neural tube defects, but studies demonstrate the other B-vitamins also might play a role in the development of this birth defect.
In addition, B-vitamin deficiency might otherwise negatively impact childhood cognitive development. One study found that the functional B12 status of infants had a direct link to the cognitive functioning of the children at 5 years of age. Lower B12 status increased the chance that the child was in the lower quartile for problem-solving scores on the tests, and there was also an association with visuospatial processing skills and social perception abilities.
The importance of adequate B-vitamin intake and cognitive health continues as you age. According to one study, the quintile with the highest intake of niacin as young adults had a significantly better cognitive function in midlife than those in the lowest quintile. The researchers looked at the data from the CARDIA study to view the impact of niacin, folate, B6, and B12 intake during young adulthood and the corresponding cognitive function during middle age. The food intake was based on questions about previous month eating habits as well as their supplemental use. Higher intake of B-vitamins also correlated with lower calorie, cholesterol, and saturated fat intake, as well as higher vitamin C and E intake.
For those with higher intakes from both supplements and food course of B-vitamins, there was a better psychomotor speed, especially for Caucasian individuals with a lower education level.
Another recent study found a relationship between folate deficiency and an increased risk of Alzheimer’s disease (AD). The study was small with patients with either AD or mild cognitive impairment, 11 of whom were positive for amyloid beta proteins, a marker and potential cause of AD. Almost 90 percent (7 of 8) of the patients who tested positive for amyloid proteins also had folate deficiency without anemia, while 3 out of 5 had either folate deficiency or anemia, as did two of the negative amyloid patients. The researchers postulate that reviewing the serum levels of folate and hemoglobin might provide an accurate biomarker for the accumulation of amyloid beta proteins, which could make it a potential biomarker of AD.
Chronic inflammation is related to many chronic illnesses, including dementia, diabetes, and heart disease. One marker for this inflammation is C-reactive protein, and there might be an inverse relationship between the levels of this marker and B5, or pantothenic acid. In one study, the researchers found an inverse association between C-reactive protein levels and dietary intake of pantothenic acid. The study used a food frequency questionnaire to determine intake of B5. This relationship might be due to a possible inflammatory effect of B5.
In a cross-sectional survey of rural Chinese adults, intake of B6 and folate was inversely associated with hypertension. Those with the highest intake of B6 had roughly three-quarters the risk of developing hypertension as the lowest intake. Although there was no association between intake of B12 and folate directly on hypertension, the women who also consumed high levels of folate had an even stronger association between B6 and hypertension. In females, there was a reduction of 36 percent of the prevalence of hypertension in the highest quartile of B6 intake from diet compared to the lowest, even after adjusting for confounding data. Although men did not have any significant associations, those in the highest quartile of B6 intake did have a lower risk compared to the lowest quartile.
Sufficient B-vitamin intake might also impact ovarian health in women. One study looking at a prospective cohort of 259 women found an inverse correlation between plasma homocysteine levels and total estradiol levels throughout the menstrual cycle, FSH levels during ovulation, and progesterone during the luteal phase. There was also a 33 percent higher risk of sporadic anovulation (not ovulating) when there were higher levels of homocysteine. Conversely, there was a lower risk of anovulation when the folate to homocysteine ratio was higher. Homocysteine levels are known to be inversely associated with B-vitamin levels.
Another study with some of the same researchers found that intake of synthetic forms of folate, not dietary forms, were associated with higher levels of progesterone during the luteal phase and inversely associated with the risk of anovulation. Further insight into the importance of B-vitamins with reproductive health comes from a study that showed an inverse risk of developing endometriosis and intake of thiamine and folate from food. However, the researchers suspect that the foods might have other phytonutrients in b-vitamin-rich foods that provide the protective effects, since there were not similar findings from supplements of these micronutrients.
B-vitamins also have other important impacts on the aging body. According to one study, higher intake of vitamin B6 was associated with a reduced risk of impaired mobility in adults over the age of 60. Data taken from the Seniors – ENRICA cohort was used to compare the intake of B6, B12, and folate from the diet rather than supplements and the agility, mobility, and physical functioning of the participants. There was an association between the three vitamins. Those in the higher quartile of each B vitamin had a higher intake of the other two, especially B6 and folate. They tended to also be more physically active and less depressed than the lower quartile. An increase of 0.5 mg/day of B6 had a 19 percent lower risk of having impaired mobility, which became borderline significant when adjusted for B12 and folate. There was a significant association between a risk of impaired agility and B6 intake.
Consuming adequate B6 might be important to help reduce your cancer risk, especially for gastrointestinal cancers. According to a systematic review that included intervention and observation studies, there was a correlation between B6 intake or serum markers and a lower risk of developing cancer. There was an inverse dose-response relationship between cancer and intake of vitamin B6, with a 6 percent reduction in risk for each milligram consumed each day. This is most likely due to B6’s role in methylation, DNA synthesis, DNA repair, inflammation, oxidative stress, and other important body processes. In this systematic review, the observational studies demonstrated a higher reduction in risk than intervention studies.
How to Ensure Adequate B-Vitamin Levels
Most of the B-vitamins are found in a wide variety of food sources, including meat, grains, fruits, and vegetables. The exception is B12, which is found only in animal sources.
Compared to the typical SAD (Standard American Diet), the Mediterranean diet has been shown to provide adequate amounts of most essential nutrients, including the B-complex, in adults and children. This is largely due to the emphasis on fruits and vegetables, legumes, green leafy vegetables, whole grains, poultry and fish, and complementary healthy lifestyle factors such as not smoking and physical activity. In one study, the higher adherence to the Mediterranean diet led to better nutritional adequacy, while a greater adherence to a Western diet led to a higher risk of nutritional inadequacy. As the adherence to the Western diet increased, the value of micronutrient levels decreased with the exception of sodium, B12, and B3, because of the high intakes of meat.
You do not have to adhere to any specific type of diet or food plan to get your B vitamins. Below are some of the best sources in decreasing order of each of the vitamins in the B family:
- B1: lentils, black beans, soybeans, navy beans, macadamia nuts, sesame seeds, split peas, tomatoes, pinto beans, and mung beans
- B2: liver and other organ meats, whey, almonds, soybeans, eggs, and buckwheat
- B3: turkey, salmon, peanuts, lamb, chicken, brown rice, buckwheat, spelt, millet, and sunflower seeds
- B5: liver, sunflower seeds, turkey, whey, eggs, shitake mushrooms, lentils, mung beans, split peas, avocados, and salmon
- B6: turkey, pistachios, garlic, amaranth, sesame seeds, chickpeas, sunflower seeds, potatoes, and lentils
- B7: organ meats, fish, eggs, seeds, nuts, and sweet potatoes
- B9: mung beans, adzuki beans, chickpeas, pinto beans, lentils, black beans, chicken, liver, and rice
- B12: beef, lamb, liver, clams, duck, oysters, salmon, chicken, mackerel, crab, and turkey
Although most healthy diets provide adequate levels of B-vitamins, some people might need to enhance their levels regardless of their diet. For example, those with the common MTHFR polymorphism, which causes an enzyme deficiency that reduces methylation, leads to a higher requirement of B-vitamins, especially folate and B12. Strict vegans and some vegetarians generally need to supplement with B12, since it is found solely in animal products. The elderly are at an increased risk of B12 deficiency and might need to supplement as well.
Here are some tips for supplementing:
- Choosing a B-complex is a good way to ensure you continue to have a balance of the B-vitamins. Folate and vitamin B12 have a close relationship, and taking one supplement might contribute to a higher requirement of the other. Additionally, supplementing with one might mask a deficiency of the other. B6 also has a close relationship with folate, and supplementing with just one might lead to a functional deficiency of the other.
- For many people, such as those with the MTHFR mutation, it is best to find methylated B-vitamin supplementation, especially for folate.
- Ensure you have adequate magnesium levels. Thiamine deficiency is further exacerbated by magnesium deficiency, and supplementing with both often helps to overcome issues from deficiency like Wernicke Korsakoff Syndrome. Magnesium and B6 have a synergetic effect, with magnesium increasing the uptake of B6 and vice versa, which is why it is best to supplement both together.
Safety of B-Vitamin Supplements
Although water soluble, excessive levels of B-vitamins are not necessarily protective. In some cases, they might create a pro-oxidative state, which might contribute to problems. Although supplementation might be necessary for some people, it should be done with care and under supervision. Some studies have found that taking B-vitamin supplements might increase the risk of certain diseases or disorders:
Men with a history of smoking might want to be cautious as to their vitamin B supplementation. In a study using data from the Vitamins and Lifestyle (VITAL) cohort, men taking vitamins B6 and B12 individually, not as part of a multi-vitamin, had an increased risk in the risk of developing lung cancer. Those who consumed the highest amounts (more than 20 mg/day for B6 and more than 55 ug/day for B12) had twice the risk as those who did not take vitamins. This was even higher for the men who were smokers at the start of the study.
Taking high doses of B-vitamins in supplement form might also increase the risk of developing cataracts, especially in those under 60 years old. In a population-based study, the participants who took high doses of vitamin B supplements as well as other vitamins had a 9 percent higher risk of developing cataracts, while those who took only vitamin B supplements had a 27 percent higher risk compared to those who did not take supplements. Upon stratifying for age, the risk for those under 60 was 1.88, which dropped to 1.21 for those in their 60s and 1.09 for those over the age of 70.
In general, supplementing with B-vitamins is safe, but it is always best to discuss your own unique needs and risks with your doctor. The tolerable upper intake levels for adults, as determined by the Food and Nutrition Board, Institute of Medicine, National Academies, is as follows:
– B1: Not determined
– B2: Not determined
– B3: 35 mg/day
– B5: Not determined
– B6: 100 mg/day
– B7: Not determined
– B9: 1,000 ug/day
– B12: Not determined
Just because there is no determined upper limit for some of the B-vitamins does not mean they are safe at any amounts. It means there is a lack of data demonstrating adverse effects that might lead to a cause for concern.
Some of the issues discussed above arising from supplementing with B-vitamins might be mitigated through taking a supplement that has a balanced ratio of the B-vitamins and other nutrients, such as magnesium. One thing is for certain: you want to ensure you have adequate intake of all the B-vitamins for optimal health. Thankfully, it is generally easy to find foods rich in these vitamins!