When you’re thinking about the complex world of nutrition, you can’t forget about a group of vitamins: B vitamins, also referred to as B complex. B vitamins are a group of water-soluble vitamins that are essential for maintaining energy and vitality.
B vitamins support metabolism, brain cell function and brain health, cellular health, new blood cell production, skin health, and more. B vitamin deficiencies increase your risk of a variety of health issues, including neurological, brain, and mental health issues, cellular dysfunction, metabolic problems, digestive issues, and skin problems.
In this article, I want to delve into the topic of B vitamins. What are they? What are the risks and symptoms of developing a vitamin B deficiency? What are the best vitamin B foods and supplementation? Join me on this journey into the world of B vitamins.
What Are B Vitamins?
B vitamins are a group of vitamins your body needs for proper cellular function. B vitamins help your body to convert the food you consume into energy. They support metabolism, brain cell function and brain health, cellular health, new blood cell production, skin health, and more. Together, the main B vitamins are called vitamin B complex. Many foods are high in a variety of these B vitamins. You will learn more about the B vitamin-rich foods later in this article. You can find B complex supplements at most pharmacies and health food stores.
B vitamins in the vitamin B complex include:
- thiamin (vitamin B1)
- riboflavin (vitamin B2)
- niacin (vitamin B3)
- pantothenic acid (vitamin B5)
- vitamin B6
- biotin (vitamin B7)
- folate (vitamin B9)
- vitamin B12
The Role of Each B Vitamin
Let’s look at the role of each B vitamin.
Vitamin B1: Thiamine
Vitamin B1, otherwise known as thiamine, is essential for your nervous system function, nerve transition, metabolism of carbohydrates into energy, and adrenal function. According to a 2020 study published in CNS Neuroscience and Therapeutics, vitamins B1, B6, and B12 are critical for your nervous system function (1). Deficiencies increase the risk of neurological, brain health, and mental health issues. According to a 1996 review published in the International Journal of Clinical Pharmacology and Therapeutics, benfotiamine (S-benzoyl thiamine O-monophosphate) is the best form of thiamine and is 3.6 times more bioavailable than thiamine salt (2).
Vitamin B2: Riboflavin
Vitamin B2, also known as riboflavin, is essential for normal metabolic functions. It also helps to recycle glutathione in your body. According to a 2017 review published in Critical Reviews in Food Science and Metabolism, deficiencies in vitamin B2 increase the risk of poor iron absorption, mitochondrial dysfunction, gut health problems, poor metabolism of tryptophan and many vitamins, brain dysfunction, and skin disorders (3). Riboflavin 5’-phosphate sodium (R5P) is the most activated form of vitamin B2 (4).
Vitamin B3: Niacin
Vitamin B3 is mostly known as niacin. It is critical for energy production. It helps the conversion of dietary fats, carbohydrates, and proteins for energy, and allows starches to be stored for energy in your muscles and liver. Niacin is also critical for your brain and mental health. According to a 2018 study published in Nutrients, it may be beneficial for patients with bipolar II disorder (5). According to a 2023 study published in the Journal of Affective Disorders, there is be a U-shaped association between niacin and depression, thus, the benefits depend on the level of depression (6). There are two key forms of niacin: nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP).
Vitamin B5: Pantothenic Acid
Vitamin B5, also known as pantothenic acid, is critical for metabolism. It plays a role in synthesizing coenzyme A. It helps fats, carbs, and proteins to be used as fuel. It is also essential for skin health. According to a 2014 study published in Dermatology and Therapy, vitamin B5 can help with acne and skin inflammation (7).
Vitamin B6
Vitamin B6 helps the production of red blood cells, balances hormones, balances sodium and potassium levels, and supports immune function. A 2020 study published in CNS Neuroscience and Therapeutics has found that along with vitamin B1 and B12, vitamin B6 is critical for your nervous system function (1), for brain and mental health. According to a 2022 research published in Human Psychopathology, it can help to reduce symptoms of depression and anxiety (8). Vitamin B6 deficiencies increase the risk of anemia, anxiety, depression, nerve damage, and skin issues. Though most supplements offer inactivated pyridoxine, the activated (pyridoxal-5-phosphate, abbreviated as PLP) form may be more effective.
Vitamin B7: Biotin
Vitamin B7, or also known as biotin, is critical for metabolic processes, nervous system function, and adrenal health. It helps to support healthy blood sugar levels. According to a 2022 study published in Frontiers in Nutrition, biotin supplementation can improve fasting glucose, cholesterol, and triglyceride levels (9). Though research evidence is limited on this, biotin may help with skin, hair, and nail health (10).
Vitamin B9: Folate
Vitamin B9 is also known as folate. It supports DNA and RNA production, and cellular and tissue growth. It works together with vitamin B12 to allow the production of red blood cells and support iron function. Adequate levels of folate are particularly important during pregnancy, infancy, childhood, and teenage years when growth is rapid and important (11). According to a 2017 research published in the European Journal of Nutrition, vitamin B9 supplementation during pregnancy supports the growth of the baby (12). Deficiencies in active folate are common due to MTHFR gene mutations, gastrointestinal disorders, poor diet, food processing issues, alcohol misuse disorder, and eating disorders (13). The bioactive forms of vitamin B9 include folinic acid, calcium folinate, and methyl-folate. Choosing L-methyl folate (glucosamine or calcium salt versions), and folinic acid are better options, especially if you have MTHFR gene mutation.
Research has shown that individuals with autism spectrum disorder, and more recently PANS/PANDAS, may be dealing with an autoimmune response against the folate receptors of the brain (14, 15, 16). This would result in folate deficiency inside the brain, but not in the bloodstream, leading to irritability, developmental delay, low muscle tone, and even seizures. The good news is, in this type of compartmental deficiency (common in functional medicine circles), a high dose prescription of folinic acid specifically has been shown to help override the deficiency and improve symptoms in a subset of individuals with autism.
Vitamin B12
Vitamin B12 is one of the most important B vitamins. It is critical for nerve function, brain and mental health, sleep, and blood cell formation, and cardiovascular function. A 2020 study published in CNS Neuroscience and Therapeutics has found that along with vitamin B1 and B9, vitamin B12 is critical for your nervous system function (1). According to a 2020 research published in Cureus, vitamin B12 may help to reduce depression (17). Methylcobalamin is a more bioactive form of vitamin B12 than cyanocobalamin. Supplementation is particularly critical for vegans and vegetarians, since vitamin B12 is only found in animal foods.
And again, related to autism in particular, B12 in its methylated form has been shown to help with oxidative stress in this patient group, including the recycling of the key antioxidant glutathione (18). The use of methyl B12 in injectable form has been shown clinically to benefit children on the autism spectrum where deemed appropriate, closely aligned with the use of folinic acid.
Benefits of B Vitamins
Working together, B vitamins offer a long list of potential benefits, including promoting:
- Cellular health
- Growth of red blood cells
- Energy
- Nerve function
- Brain function
- Mental health
- Hormonal health
- Cardiovascular health
- Normal blood sugar, cholesterol, and triglyceride levels
- Digestion
- Muscle health
- Skin health
- Eye health
Symptoms of Vitamin B Deficiency
Symptoms of vitamin B deficiency depend on the level of deficiency, length of deficiency, and the type of vitamin B you are deficient in.
Symptoms of vitamin B deficiency include:
- Fatigue
- Weakness
- Heart palpitation
- Shortness of breath
- Irritability or depression
- Anxiety
- Confusion
- Abdominal cramps and pain
- Constipation or diarrhea
- Nausea
- Loss of appetite
- Skin rashes
- Scaly skin on the lips
- Cracks around the mouths
- Swollen tongue
- Tingling in the feet or hands
- Anemia
Causes of Vitamin B Deficiency
You can have an increased risk for developing vitamin B deficiency for a variety of reasons, including:
- Genetics: MTHFR gene mutations (19)
- Poor diet, low in vitamin B foods, and vegan or vegetarian diets for vitamin B12 deficiency (20)
- Eating disorders and other causes of malnourishment (22)
- Gut infections, vitamin malabsorption, and other gut health issues (23)
- Gastric surgeries (24)
- Chronic stress (25)
- Certain medications, including H2 receptor blockers and proton pump inhibitors, colchicine for gout, ethanol, metformin for diabetes, chloramphenicol antibiotics, and levodopa and carbidopa for Parkinson’s disease (26, 27)
- Autoimmune disorders (28)
- Chronic inflammation and oxidative stress (29)
- Alcohol use disorders (30)
- Pernicious anemia (31)
MTHFR Mutations, Methylation, and B Vitamins
The methylenetetrahydrofolate reductase (MTHFR) gene helps to make the MTHFR enzyme. It helps various biochemical reactions in your body. One of these biochemical reactions is called methylation, which refers to the process of converting folate into methylfolate. Proper methylation is essential for metabolizing B vitamins, DNA function, cellular function, repairing damaged cells, hormonal health, mental health, sleep, and detoxification.
MTHFR gene mutations are a very common genetic mutation. It may affect up to 40% of the population. Caucasians and Hispanics are at higher risk (33, 34). MTHFR gene mutation increases methylation issues, which increases the risk of fatigue, low energy, sleep problems, mental health issues, metabolic issues, histamine intolerance, food sensitivities, chemical sensitivities, hormonal health issues, and other chronic health issues (35, 36, 37, 38).
If you have MTHFR gene mutations and are dealing with methylation issues, it could be very important for you to consider pre-methylated vitamin B supplements, with guidance from your health provider, and follow a diet rich in B vitamins. There are nuances. You’ll learn more about the methylation cycle and MTHFR mutations here and here.
Foods High in Vitamin B
The best vitamin B-rich foods include:
- Best vitamin B1 (thiamine) foods include: dark green vegetables, pasture-raised eggs, sunflower seeds, black seeds, and black beans
- Best vitamin B2 (riboflavin) foods include: dark green vegetables, almonds, grass-fed beef and lamb, salmon and other wild-caught oily fish, grass-fed raw cheese, and pasture-raised eggs
- Best vitamin B3 (niacin) foods include: wild-caught salmon, tuna, pasture-raised chicken and turkey, grass-fed beef, and liver
- Best vitamin B5 (pantothenic acid) foods include: mushrooms, oily wild-caught fish (e.g., trout and salmon), and grass-fed raw cheese
- Best vitamin B6 (pyridoxine) foods include: garbanzo beans, wild-caught salmon, tuna, pasture-raised chicken, and beef liver
- Best vitamin B7 (biotin) foods include: nuts and seeds, wild-caught fish, organ meats, and pasture-raised eggs
- Best vitamin B9 (folate) foods include: avocados, sprouting broccoli, asparagus spinach, pasture-raised eggs, and liver
- Best vitamin B12 foods include: wild-caught fish, pasture-raised poultry, and pasture-raised eggs, and grass-fed beef. There are no plant food sources of vitamin B12, and even those who eat animal products can have difficulties meeting their vitamin B12 needs through diet alone. If you are a vegan, vegetarian, or mostly plant-based, supplementing with vitamin B12 is non-negotiable. But even if you are eating a diet high in animal foods, you may likely benefit from vitamin B12 supplementation, as deficiencies are common.
Supplementing with Vitamin B
Though eating a healthy whole food diet is the ideal way to meet your vitamin needs and the best way to absorb B vitamins, you may also benefit from supplementation if you have low levels of B vitamins or are at risk of developing a deficiency.
You are more likely to benefit from B vitamin supplementation if you are:
- 50 or older
- Pregnant or breastfeeding
- Have chronic health conditions
- Taking medications that increase the risk of vitamin B deficiency
- Following a vegan, vegetarian, highly plant-based, meat-free diet
I recommend working with your doctor before taking vitamin B or any other supplements. Choose a trusted, reputable brand with high-quality ingredients and follow the directions and your doctor’s recommendations carefully.
Since B vitamins are water-soluble and any excess should be removed through urine, getting too much B vitamins is unlikely. However, it is still important that you don’t take more than recommended. Excess vitamin B6 can increase the risk of peripheral neuropathy. Excess folate may cover up vitamin B12 deficiency symptoms and increase the risk of nerve damage. Too much niacin might lead to liver issues. As an acute side effect, too much niacin can cause skin flushing.
Next Steps
If you are dealing with symptoms of low vitamin B levels, I invite you to schedule a consultation with me here to see if you can benefit from the strategies listed in this article.
If you are dealing with any chronic health issues, for advice on how to improve your nutrition and health, I welcome you to start a functional medicine consultation with me for further personalized guidance. Book your consultation here.
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