| Are you on the B list?
B group vitamins are water-soluble compounds that are not stored in the body for long and so need to be replenished more frequently. Dr Wynnie Chan explains why we need them The B group of vitamins comprises thiamin (B1), riboflavin (B2), niacin (nicotinic acid), folate (folic acid), vitamin B6, vitamin B12, biotin and pantothenic acid. Thiamin (B1) Sources: Thiamin is found in both animal and vegetable foods. Good sources include milk and dairy foods (except butter), offal, pork, eggs, vegetables and fruit, wholegrain cereals, pulses nuts, beans, peas and fortified breakfast cereals. As thiamin is water soluble, large amounts can be easily lost when vegetables, for example, are cooked in water and the excess is discarded. Adding bicarbonate of soda to water used for cooking foods rich in thiamin will result in almost the entire vitamin being destroyed. B1 content of selected foods in mg per 100g of food
Recommended intake: requirement for this vitamin is related to the amount of energy or calories gained from your diet, but for adults it is 0.4mg per 1,000kcal. Deficiency: Beri beri is a disease that can result from a diet rich in carbohydrates or alcohol and poor in vitamin B1. Toxicity: long-term intake of more than 3g vitamin B1 a day may have adverse effects on the body. Riboflavin (B2) Sources: Riboflavin is found in a wide variety of foods. Rich sources of the vitamin include milk, cheese, offal, eggs, fortified breakfast cereals, meat and meat products. Vitamin B2 is easily destroyed by sunlight so doorstep milk should be taken in as soon as possible to avoid loss. B2 content of selected food mg per 100g of food
Requirements: The recommended daily intake of the vitamin is 1.1mg a day for adult women and 1.3mg a day for adult men. Deficiency: This is rare but symptoms can include sores at the corners of the mouth. Toxicity: This has rarely been seen. This vitamin is not very soluble in the gut and so it is unlikely that large amounts could be absorbed to cause problems. Niacin (B3) Sources: This vitamin is found in a wide variety of foods. Rich sources of the vitamin include meat and meat products, bread and fortified breakfast cereals. Potatoes, pulses, milk and milk products and fish contain moderate amounts. Niacin content of selected foods mg per 100g of food
Recommended intake: This is related to energy requirements and is 6.6mg per 1,000kcals for all ages; breastfeeding women need an additional 2.3mg per day. Deficiency: Pellagra is a disease that results from niacin deficiency, characterised by the skin becoming dark and scaly in parts exposed to sunlight. Toxicity: Very high doses of 3g–6g a day may cause liver damage in some people. A few will experience a burning sensation in the face and hands. Pyridoxine (B6) Sources: Vitamin B6 is found in a wide variety of foods such as cereals, fruits, leafy vegetables and liver. B6 content of selected foods mg per 100g of food
Recommended intake: Requirements are related to protein intake and is 15ug per g protein. Deficiency: This is rare. Toxicity: Very high intakes of more than 50mg may damage nerve function. The government’s advice is for people to limit their intake from vitamin supplements to no more than 10mg a day unless their doctor advises otherwise. Folate (Folic acid) Sources: Folate is found in many foods, rich sources include green leafy vegetables, potatoes, fortified breakfast cereals, fortified bread, offal, nuts and beans. Fruit, yeast extract meat and dairy products contain small amounts. Folate is readily lost in cooking water. Folate content of selected foods ug per 100g of food
Recommended intake: 200ug a day for adults. Pregnant and lactating women need an additional 100ug and 60ug a day respectively. In addition, all pregnant women up to the 12th week of pregnancy and those planning to conceive are advised to take a daily supplement of 400ug folic acid (folic acid is the synthetic form of folate) to reduce the risk of having a baby with a neural tube defect. Deficiency: A type of anaemia called megaloblastic anaemia occurs as a result of a deficiency in folate. Deficiency can occur from a poor diet, increased requirements during pregnancy or in gastrointestional diseases that prevents folate from being absorbed from the gut. Toxicity: High intakes can lead to zinc being poorly absorbed from the diet. Liver is a rich source of the vitamin but should be avoided by pregnant women because it also contains high levels of vitamin A, which can damage the unborn baby. Vitamin B12 Sources: Vitamin B12 is found only in animal products and in yeast. The richest source of the vitamin is liver but other foods such as eggs, cheese, milk, meat, fish and fortified breakfast cereals contain useful amounts. Vitamin B12 content of selected foods ug per 100g of food
Recommended intakes: The recommended intake of B12 is 1.50pu a day for adults; lactating women need an extra 0.5ug a day. Deficiency: A type of anaemia called pernicious anaemia develops as a result of B12 deficiency; nerves are also damaged. Toxicity: High intakes of up to 3mg a day have not shown any harmful effects in adults. Biotin Pantothenic acid |