The B vitamins are a group of vitamins necessary for energy production, central nervous system function and the production of numerous components of the blood. They are also involved in the recycling of homocysteine, high levels of which are a key risk marker for a number of modern conditions including heart disease and Alzheimer’s.
Vitamin B1 (thiamine)
Essential for carbohydrate metabolism and energy production, as well as playing a role in nerve impulse conduction. Acting as a coenzyme (a molecule that aids the activity of an enzyme) for three enzyme complexes involved in energy-generating pathways, thiamine helps facilitate a series of chemical reactions that result in energy release. Thiamine deficiency is associated with very heavy alcohol intake, poor diet (highly processed food and refined carbohydrates or insufficient intake of food), or persistent vomiting. Conditions caused by thiamine deficiency are severe and affect function of the brain and limbs. Unless you fall into the above categories you are unlikely to suffer any thiamine-related issues but maintaining adequate intake is still important. Daily requirements depend on the amount of carbohydrate eaten and should be at least 0.8mg per day for women and 1mg for men. People eating a highly refined carbohydrate diet need and should consider including more thiamine in their diet. Good sources of vitamin B1 include pork, vegetables, milk, eggs and wholegrain bread. Vitamin B1 cannot be stored and so must be eaten every day. It is not necessary to supplement as daily requirements can be met by the diet alone.
Vitamin B2 (riboflavin)
Acts as a coenzyme, working to aid metabolic processes crucial for unlocking the energy stored in macronutrients. Deficiency can be due to poor diet or an inability to absorb dietary sources. The overall result of deficiency is a reduced ability to metabolise fats, which stunts growth and prevents normal development. Signs and symptoms may include badly cracked lips and a dry, painful mouth and tongue, dry skin and bloodshot eyes, but deficiency is rarely fatal. The main sources of vitamin B2 are dairy products, although eggs, nuts, leafy green vegetables and lean meats provide good alternative sources. Adults should aim to eat about 1.5mg every day, as it is a water-soluble vitamin and so unable to be stored in the body. It is sensitive to light, so foods should be kept in dark containers and eaten soon after cooking. Mushrooms, spinach and almonds are particularly tasty, excellent sources of B2.
Vitamin B3 (niacin)
Involved in the activity of signalling molecules necessary for the functioning of enzymes important for biological processes such as energy metabolism, mitochondrial function, calcium homeostasis, reducing oxidative stress, gene expression, immune function, ageing and cell death. Whilst the benefits of taking niacin to boost these and other cellular functions is still poorly understood, niacin is known to play a very important role in cholesterol metabolism and its use increases HDL cholesterol whilst lowering LDL cholesterol, as well as triglycerides. Niacin may, however, decrease insulin sensitivity when used long term.
Nicotinamide, also known as niacinamide, may also be referred to as vitamin B3 as it has vitamin-like properties.
Niacin is found in liver and organ meats as well as eggs, fish and legumes. The recommended daily intake of niacin is 17 mg for men and 13 mg for women. It is not usually necessary to supplement with vitamin B3 and if doing so seek professional guidance.
Vitamin B5 (pantothenic acid)
Essential to the manufacture of coenzyme A and acyl carrier proteins, both of which contribute to fat and carbohydrate utilisation for energy and the production of biological proteins, hormones and red blood cells. Deficiency of B5 is very rare as it is found in small amounts in a large number of foods. Foods particularly rich in Vitamin B5 include liver and organ meats as well as most animal-origin foods, whole grains, legumes and most fruits and vegetables. Vitamin B5 plays an important role in almost every cellular function and so a diet deficient in B5 can have very detrimental effects on health. Studies have found that supplementing with vitamin B5 can be beneficial for the health of the adrenal glands, which are important for our stress management systems; it also has a role in helping to alleviate inflammatory joint issues, maintaining healthy cholesterol and lipid levels, as well as supporting mental performance. Adults should consume at least 7mg daily from a range of food sources.
Plays its role in energy metabolism as well but is also important in the synthesis of haemoglobin, the component of blood that binds and transports oxygen around the body. Both of these roles are fundamental for maintaining optimal energy levels. It also acts on DNA to help regulate the release of steroid hormones, as well as being important for cognitive development. Deficiency is uncommon and most people are able to meet their daily needs through diet alone. Good sources of vitamin B6 include beef, poultry and fish, along with many of the vegetables that provide the other B vitamins. Toxicity due to over-consumption from foods is not known to be a problem, but can be observed in those taking supplements long term. Loss of feeling in the limbs can be a sign that vitamin B6 levels have become toxic, as well as skin lesions and gastrointestinal problems, including nausea. In most cases, symptoms will cease once supplementation is stopped. Adults should aim to eat more than 1.2mg per day from wholefood sources. Supplementary vitamin B6 might be necessary for people with renal dysfunction, autoimmune disease and alcohol dependence.
A little known B vitamin, most commonly associated with skin and hair health. Whilst little research has shown that increasing biotin levels beyond those required for normal health will promote greater hair and skin health, a deficiency of biotin will certainly contribute brittle, damaged and flaky skin, hair and nails. Biotin is a coenzyme necessary for the synthesis of fatty acids, amino acids and glucose production from non-carbohydrate sources such as pyruvate and lactate. Biotin plays an important role in cell growth and repair and energy metabolism. Cheese, organ meats, whole wheat and soybeans are good sources of biotin, as well as eggs, mushroom, leafy greens and legumes. Most people should have adequate biotin in the diet, although those consuming high levels of alcohol or with digestive and absorption issues such as following partial or full gastrectomy may require extra supplementation.
More commonly found in food and supplements as folic acid, and until recently the two were considered interchangeable. Folic acid, although found in the body, is not the form that naturally occurs in food and so many supplement manufacturers are switching to folates to avoid use of the synthetic folic acid, which can, for some people, be hard to metabolise due to the extra steps involved in its processing. Folate is the term used for a group of vitamins also known as B9 which is vital for the formation of red blood cells, the recycling of homocysteine and nervous system function. Folate is best known for its role in preventing neural tube defects in newborns, and folic acid is now added to all flour in the UK to ensure that women of childbearing age have an adequate intake prior to and during pregnancy. Most people consuming flour-based products therefore do not require extra folate supplementation, but in some cases it may be necessary to increase folate intake through diet and supplements. For example, anyone with mood-related disorders and heart complications, as well as those at risk of dementia, may benefit from increased folate due its important role in recycling homocysteine, high levels of which are known to increase risk of these conditions. As with the other B vitamins, folate is found in high levels in liver as well and leafy green vegetables and legumes. Anyone consuming a diet rich in vegetables will be getting the recommended 400mcg per day of folate but women trying to conceive or in the early phases of pregnancy may need to supplement as requirements can be double this amount or more.
Another water-soluble vitamin, is ingested bound to protein in our food. It is released by the digestion process in the stomach and used as a coenzyme for a number of reactions involved in the synthesis of haemoglobin, DNA, hormones and the metabolism of fat and protein. Deficiency can cause weakness, fatigue, loss of appetite, constipation and eventually megaloblastic anaemia. Low vitamin status without full deficiency can have a number of neurological implications, including numbness of the hands and feet, balance loss, confusion and memory loss and – in the advanced stages – depression and dementia. Daily intakes of 2.4micrograms are considered adequate for everyone over 14 years, with animal products, particularly fish and beef, being the highest dietary sources. Fortified foods such as breakfast cereals and dairy products can be useful alternatives for vegetarians and those with a restricted diet. Vitamin B12 levels are thought to be adequate in most of the population but certain groups are at risk of poor status. Older people and anyone with digestive or intestinal complications may have a reduced capacity for absorbing this essential nutrient. Vegetarians may not ingest enough high vitamin sources unless eating fortified cereals daily, along with dairy products. For these ‘at risk’ groups, supplementation may be an option if dietary intake cannot be modified to meet individual needs.