As colder weather hits, sales of vitamin supplements soar. In 2022, 43.5% of Australians bought vitamins. The top seller was vitamin D, followed closely by multivitamins, vitamin C and vitamin B.
I’ve written about vitamin D previously. And I’ve also noted that dozens of studies have not found any evidence that taking vitamin C can reduce the incidence of colds.
This article is about the B complex. Years ago, 12 different compounds were assumed to be part of this complex and assigned numbers B1 to B12. However, researchers have found that only 8 of the original compounds are actually vitamins. Some of the numbers have stuck, but it’s probably better to use the correct name.
B1 – thiamin, often incorrectly given an extra ‘e’ by spell-checkers and product labels. The ‘e’ was removed years ago when vitamins (previously called ‘vitamines’) were found not to be ‘amines’. Like many members of the B complex, thiamin is involved in the body’s ability to extract energy from carbohydrates, fats and some of the amino acids that make up protein. The best sources are wholegrains (especially wheat, wholegrain breakfast cereals including oats, muesli, Weetbix), legumes, nuts, seeds, pork, green peas and Vegemite. Deficiency causes beri-beri, a disease, usually seen only in starvation.
B2 – riboflavin is also involved in the release of energy from foods and is a powerful antioxidant (It is also responsible for the ‘burps’ that many people experience with multivitamins). The richest sources include yoghurt and other dairy products, high-fibre breakfast cereals, liver, kidney, chicken, almonds and, again, Vegemite. Adding carb soda, vinegar or lemon juice during cooking leads to losses, so it’s best to squeeze lemon or vinegar onto foods after cooking. Deficiency is usually only seen with high consumption of alcohol.
B3 – niacin is made up of two compounds, nicotinic acid and nicotinamide. This vitamin assists cells to use energy and DNA for repair processes throughout life. About half of the body’s niacin is made from an amino acid called tryptophan. This reaction increases dramatically during pregnancy and with oral contraceptive pills and is a major reason for women to avoid niacin supplements. An excess can reduce blood cholesterol but side effects include hot flushes, skin rashes and increased risk of gout. Best to stick to foods, which include tuna, salmon and other fish, nuts, peanuts, liver and meat, wholegrains, legumes, seeds, dairy or soy beverages, mushrooms, avocado – and Vegemite. Deficiency causes pellagra, seen only in severe starvation.
Pantothenic acid (also called pantothenate and previously B5) is widely distributed in foods and takes part as a co-enzyme in thousands of biochemical reactions in the body. This vitamin has different effects in different animals. For example, it stops rats’ hair turning grey, but has no such effect in humans – although such claims help sales! Liver and caviar are the richest sources, but neither is necessary due to pantothenic acid’s wide distribution in foods. Deficiency is only seen in long-term starvation. Claims for supplements of royal jelly are unfounded – best to leave it for genuine queen bees!
B6 – commonly called pyridoxine, is made up of three substances: pyridoxal, pyridoxine and pyridoxamine. These all act as co-enzymes and can be interconverted within the body. About 80-90% of the body’s B6 is stored in muscles and plays an important role during exercise. The vitamin is also needed for many reactions, including the way the body handles riboflavin. Vitamin B6 is widely distributed in animal foods (mainly as pyridoxal) and plant foods (as pyridoxine and pyridoxamine) and deficiency is unlikely. Top sources include soy products, muesli and bran cereals, wholegrains, meat, poultry, fish, avocado, potatoes, and nuts and legumes (especially walnuts, hazelnuts, cashews, peanuts, soy beans, lentils and beans).
Supplements of B6 are rarely needed and can be dangerous with some drugs used to treat epilepsy. Exceptions include some prescription drugs used for rheumatoid arthritis or kidney stones as these may alter the way the body uses B6.
Excess B6 from supplements can cause peripheral neuritis which starts with ‘pins and needles’ in fingers and toes and leads to damage of the nerve endings. The recommended dietary intake (RDI) for vitamin B6 is up to 2 mg/day, but many supplements contain far more, and hazardous quantities are added to many magnesium supplements. After serious increases in peripheral neuritis, the Therapeutic Goods Authority now requires the label of all products containing more than 10mg of B6 in the daily dose to display “WARNING – Stop taking this medication if you experience tingling, burning or numbness and see your healthcare practitioner as soon as possible. (Contains vitamin B6)”.
Folate – properly called pteroylglutamate and once known as B9 is actually a family of over 30 compounds. Its common name is now folate – think foliage, as leafy greens are an excellent source. Folate is involved in more than 100 biochemical reactions in the body, including synthesis and repair of DNA and red blood cells. Together with vitamin B12, folate also helps make an amino acid called methionine.
Folate is also found in almost every vegetable, as well as in legumes, liver, kidney, fruits, nuts, dairy products and wholegrains. Because folate is especially important in the first stages of pregnancy and can help prevent spina bifida, most bread flour and many processed breakfast cereals now have added folic acid, a synthetic form of the vitamin. This has been associated with a reduced incidence of spina bifida. However, note that more is not better and folic acid supplements can be hazardous, interfering with some medications and also masking vitamin B12 deficiency. Folate occurring naturally in foods is not a problem.
Biotin – once called vitamin H is a B complex vitamin involved as a coenzyme in many biochemical reactions in the body. It is widely distributed in foods (top sources include legumes, nuts, egg yolk, wheat, oats, rice and vegetables) and is also made by ‘good’ bacteria in the intestine. Biotin deficiency can occur with prolonged use of some medications but is mainly seen in those who eat raw egg white. Avidin, a substance in the white of all birds’ eggs, binds to biotin, making it unavailable. An occasional raw egg won’t cause problems, but eating several raw eggs regularly is hazardous.
Vitamin B12 – exists in different forms of cobalamin and is involved in making red blood cells and DNA (in conjunction with folate). The chemical structure of B12 was only worked out in 1964, although the pernicious anaemia that comes from a deficiency was first described in 1824. In 1926, medical scientists found this fatal condition could be cured by feeding beef liver.
Unlike other B vitamins, B12 is found only in animal foods. The best food sources are liver and kidney, followed by mussels, oysters, fish, rabbit, duck, red meat, chicken and eggs. Dairy foods are also a source. Very small amounts can be made in the human intestine but those who follow a vegan diet need to include specially fortified foods or a supplement – a recommendation noted and promoted by the Vegan Society. Check the label on plant-based drinks and some soy products to see if B12 has been added. Products such as spirulina, nori and comfrey contain analogues of B12 that are not useful for humans. Kombucha, tempeh and other fermented products contain only trace amounts of B12.
The RDI for adults is 2.4 micrograms/day with 2.6mcg during pregnancy and 2.8mcg during lactation. Some elderly people can have problems absorbing vitamin B12 and need a supplement.
