Water Soluble Vitamins
Here's some useful information about water soluble Vitamins B1, B2, B3, B5, B6, B12, Biotin, Vitamin C, Folic Acid and other B vitamins together with the best foods that contain them.
Vitamin B1 Thiamin
Thiamin is a water soluble vitamin which is a coenzyme involved in the metabolism of glucose into energy or to other sugars, and it works synergistically with other B vitamins. Requirements for thiamin are related to the carbohydrate and energy content of the diet. Adults should aim for 0.4mg of thiamin per 1,000kcal energy intake per day. Therefore an average sedentary female should aim for around 0.8mg and a male 1.1mg thiamin per day.
Deficiency of thiamin is called beriberi and occurs where intake of thiamin is low and carbohydrate intake is high, eg in developing countries where only one starchy staple food is primarily consumed. Thiamin deficiency also occurs in chronic alcoholism where it is called Wernicke-Korsakov syndrome. Mild thiamin deficiency can result in difficulty in concentration, irritability, depression, muscle weakness and poor coordination. Severe thiamin deficiency, as in beriberi, is characterised by mental confusion and peripheral neuropathy; oedema characterizes the 'wet' form of beriberi, and muscular atrophy, tachycardia and cardiomegaly are characteristics of the 'dry' form.
Thiamin can be lost in cooking both through high temperatures and leeching out in water. It can also be lost during milling of grains, thus some white flours may be fortified with thiamin.
Thiamin is found in good amounts in the following dietary sources:
- Brewer's yeast (2 tblsp) - 2.3mg
- Shreddies (55g) – 0.66mg
- Fruit 'n' Fibre (50g) – 0.5mg
- Muesli (95g) – 0.48mg
- All-bran (45g) – 0.45mg
- Bran Flakes (45g) – 0.45mg
- Crunchy Nut Corn Flakes (45g) – 0.45mg
- Frosties (45g) – 0.45mg
- Special K (35g) – 0.42mg
- Rice Krispies (35g) – 0.35mg
- Coco Pops (35g) – 0.35mg
- Weetabix (2 biscuits) – 0.28mg
- Corn Flakes (25g) – 0.25mg
- Wheatgerm (15g) – 0.3mg
- Wholemeal bread (1 slice) – 0.24mg
- Bagel, white enriched (60g) - 0.4mg
- Pasta, wholewheat boiled (150g) – 0.3mg
- Brown rice, cooked (165g) - 0.23mg
- Cashews (40g) – 0.17mg
- Peanuts (30g) – 0.27mg
- Brazil nuts (30g) – 0.3mg
- Hazel nuts (25mg) – 0.1mg
- Sunflower seeds (25g) - 0.6mg
- Sesame seeds (15mg) – 0.11mg
- Pork (100g) - 0.9mg
- Ham (100g) - 0.7mg
- Kidney (75g) – 0.42mg
- Liver (90g) – 0.23mg
- Plaice (120g) – 0.36mg
- Salmon (135g) – 0.22mg
- Soya milk (250ml) - 0.4mg
- Baked beans (200g) – 0.2mg
- Green peas (75g) – 0.18mg
- Potato, baked (140g) – 0.14mg
- Potato, boiled (150g) – 0.12mg
- Chips (250mg) – 0.27mg
- Sweet potato, boiled (150g) – 0.12mg
- Orange juice (250ml) - 0.2mg
Vitamin B2 Riboflavin
Riboflavin is a water soluble B vitamin which is essential for the oxidative processes on which organisms depend. Deficiency in humans results in lesions of the mucous surfaces, eg in mouth, skin lesions and vascularisation of the cornea.
Riboflavin can be responsible for some pale green/yellow colours in vegetables, but it can be lost in cooking both through high temperatures and leeching out in water. It is also sensitive to light.
Requirements are in part dependant on intakes of other nutrients. Adult females should aim of 1.1mg riboflavin per day, adult males 1.3mg per day. Riboflavin is found in good amounts in animal products and green vegetables, as well as some nuts, seeds and grains. Main sources include:
- Kidney, cooked (75g) – 1.73mg
- Liver, cooked (90g) – 3.96mg
- Beef (85g) – 0.27mg
- Lamb (85g) – 0.25mg
- Pork (85g) – 0.23mg
- Bacon (120g) – 0.29mg
- Ham (55g) – 0.14mg
- Chicken, roasted (85g) – 0.2mg
- Mackerel (110g) – 0.42mg
- Plaice (120g) – 0.3mg
- Yeast, baking (30g) - 1.51mg
- Brewers yeast (30g) - 1.19mg
- Marmite (5g) – 0.55mg
- Bovril (5g) – 0.3mg
- Milk (100ml) – 0.2mg
- Condensed milk (300g) - 1.27mg
- Cheese, Cheddar (40g) – 0.16mg
- Cheese, Edam (40g) - 0.14mg
- Feta cheese (40g) - 0.1mg
- Cheese cottage (200g) - 0.44mg
- Yogurt plain, low fat (200g) - 0.39mg
- Eggs (1 medium) – 0.24g
- Almonds (20g) – 0.18mg
- Cashew nuts (40g) – 0.1mg
- Sunflower seeds (100g) - 0.3mg
- Dried mixed fruit (100g) – 0.29mg
- All-Bran (45g) – 0.68mg
- Bran Flakes (45g) – 0.68mg
- Muesli (95g) – 0.67mg
- Shreddies (55g) – 1.21mg
- Weetabix (2 biscuits) – 0.4mg
- Cornflakes (40g) - 0.49mg
- Quinoa, cooked (170g) - 0.67mg
- Sweet potatoes, cooked (300g) - 0.4mg
- Buckwheat (170g) – 0.73mg
- Wheat germ (100g) - 0.49mg
- Cabbage, cooked (100g) - 0.1mg
- Hummus (200g) - 0.4mg
- Soya beans, cooked (150g) - 0.45mg
- Brussel sprouts, cooked (115g) – 0.12mg
- Broccoli, boiled (95g) – 0.19mg
- Spinach, boiled (130g) – 0.2mg
- Mushrooms, boiled (55g) – 0.19mg
Vitamin B3 - Niacin
Niacin is a water soluble B vitamin which includes nicotinic acid (niacinic acid) and nicotinamide (niacinamide). This vitamin functions in metabolism as a coenzyme in providing energy through NAD and NADP.
Deficiency of niacin is pellagra which is characterised by severe skin lesions in areas exposed to sunlight and pressure (eg knees), diarrhoea and dementia; eventually it is fatal.
The essential amino acid tryptophan can be converted to niacin where 60mg tryptophan = 1mg niacin. As niacin is linked to energy production, requirements increase with calorie consumption. Adults should aim for 6.6mg niacin equivalent per 1,000kcal of dietary energy.
Niacin, like other B vitamins, is quite a labile vitamin and can be lost in food preparation. Brown rice is a significant contributor to niacin intakes in some parts of developing Asia, and where the rice is polished (to white rice) pellagra incidence rises dramatically.
Good sources of niacin include:
- Liver, cooked (90g) – 18.1mg
- Kidney, cooked (75g) – 11.2mg
- Beef (85g) – 9.2mg
- Lamb (85g) – 9.4mg
- Pork (85g) – 10.4mg
- Gammon (120g) – 15.6mg
- Chicken (85g) – 13.0mg
- Turkey (85g) – 13.3mg
- Cod (130g) – 7.5mg
- Plaice (120g) – 8.0mg
- Kipper fillets (130g) – 11.4mg
- Mackerel (110g) – 14.0mg
- Salmon (135g) – 11.7mg
- Tuna, canned in oil, drained (70g) – 8.8mg
- Bacon (45g) – 5.4mg
- Bovril (5g) – 4.3mg
- Marmite (5g) – 3.4mg
- Malted milk drink (4 tsp – 20g) – 3.6mg
- Cheese, Cheddar (40g) – 2.4mg
- Cheese, Edam (40g) – 2.5mg
- Eggs (1 medium) – 2.3g
- Bread, wholemeal (medium slice) – 4.1mg
- All-Bran (45g) – 8.6mg
- Bran Flakes (45g) – 8.3mg
- Muesli (95g) – 8.4mg
- Shreddies (55g) – 12.7mg
- Weetabix (2 biscuits) – 4.8mg
- Cornflakes (40g) – 4.2mg
- Peanuts (30g) – 6.4mg
- Pasta, wholewheat, cooked (150g) – 3.5mg
- Brown rice, boiled (165g) – 3.1mg
- Broad beans, boiled (75g) – 2.8mg
- Peas, boiled (75g) – 2.2mg
- Spinach, boiled (130g) – 2.3mg
Vitamin B5 – Pantothenic Acid
Pantothenic acid is a water soluble vitamin which is an enzyme cofactor essential in the role of metabolising food for energy, and it works synergistically with other B vitamins. There are no requirements figures for pantothenic acid but intakes over 5mg per day are more than adequate. Deficiency is very rare, but symptoms include headache, fatigue, dizziness, muscle weakness and gastrointestinal disturbances.
Like other B vitamins, pantothenic acid can be lost in cooking both through high temperatures and leeching out in water.
Pantothenic acid is abundant in our diets, but particularly good sources are:
- Brewer's yeast
- Wholegrain products
- Wheat bran
- Beans and lentils
- Sweet potatoes
- Egg yolk
Vitamin B6 is a mixture of the water soluble compounds pyridoxal, pyridoxine, pyridoxamine and their phosphates, eg pyridoxal phosphate (PLP). All the compounds can be inter-converted and PLP, the active form, is a cofactor for a large number of metabolic enzymes in protein metabolism.
Requirements of vitamin B6 are related to protein intake. Adults should aim for 15µg per gram protein intake per day. Therefore an average 80g protein per day will require 1.2mg of vitamin B6. Deficiency is very rare but symptoms include convulsions and dizziness. Alcoholics are at risk due to dietary inadequacy and because alcohol promotes the destruction of B6 from the body. Vitamin B6 can be toxic in high amounts causing nerve damage to the arms and legs, but this is only from supplementation. B6 supplements have been used to reduce symptoms of pre-menstrual tension, but caution is advised.
Vitamin B6 is abundant in our diets. Cooking, storage and processing losses of vitamin B6 vary and in some foods may be more than 50%. Plant foods lose the least during processing as they contain mostly pyridoxine which is the more stable form. Milk can lose 30-70% of its vitamin B6 content when dried. Particularly good sources include:
- Wholegrain products
- Fortified breakfast cereals
- Wheat bran
- Red meat
- Beans and lentils
- Soya beans
- Sunflower seeds
Folic Acid (Folate)
Folic acid is a B vitamin and is necessary for healthy red blood cells. It has also been shown to help prevent neural tube defects (e.g. spina bifida) in pregnancy
Foods rich in folic acid include:
- Liver (not to be eaten during pregnancy)
- Leafy green vegetables, especially broccoli, spinach, dark green (Savoy) cabbage
- Runner and French beans
- Peanuts, hazel nuts
- Bread, wholemeal or white
- Oranges, bananas
- Yeast extract e.g. Marmite, Vegemite
- Fortified breakfast cereals, e.g. Cornflakes, All Bran, Rice Krispies, Weetabix, Bran Flakes
However as folic acid is easily lost from foods during cooking:
- Cook vegetables in the smallest amount of boiling water needed
- Cook for as short a time as possible
- Eat foods shortly after cooking – do not keep warm for long periods after heating
Vitamin B12 (Cyanocobalamin)
Vitamin B12 is necessary for healthy red blood cells and nerve fibres. It cannot be stored in the body, so foods rich in B12 need to be eaten every day. It is most commonly found in animal products, so those following a vegan diet need to be especially careful.
Good food sources of vitamin B12 are:
- Most meat and meat products
- Fish – all types
- Milk, cheese, yoghurts, fromage frais
- Yeast extract e.g. Marmite, Vegemite
- Fortified breakfast cereals, e.g. Cornflakes, All Bran, Rice Krispies, Grape Nuts
- Some pulses (if consumed in large quantities)
- Meat analogues fortified with B12, e.g. Quorn
- Soya milk fortified with B12
Miscellaneous B Vitamins
There are a number of other water soluble organic substances which are sometimes reported to be essential food components. Indeed there are thousands of organic compounds found in food; a few of these are often classed with the B complex vitamins. These are not 'essential' in the direct meaning of the word as they can be synthesised from other food constituents in the body; however, for some of them, consuming them from food may be metabolically advantageous.
Choline works in conjunction with folic acid and its functions are in the structure of cell members, neurotransmitter synthesis and liver protection. It is essential for brain and neural tube development in the foetus and infants.
Choline is plentiful in our diets and is easy to obtain sufficient from eating a wide variety of foods. Good sources of choline include: liver, eggs, beef, cauliflower, beans, soya and tofu, almonds and peanut butter.
Inositol is readily available from the diet as over 99% of dietary inositol is absorbed. It is also widespread in the diet and can be made in the body. Inositol functions to transport fat in the body and is important for hair nourishment.
Deficiency of inositol is rare as it is abundant, absorbed so easily and can be made in the body. Major sources of inositol are liver, brewer's yeast, grapefruit, bananas, raisins, wheat germ, nuts and peanuts, brown rice and cabbage.
PABA – Para-Amino Benzoic Acid
PABA is also related to folic acid thus is often grouped with the B vitamins. It is known as the 'sunscreen vitamin' and is often found in topical sunscreen preparations, as it can absorb UV light. It corrects loss of pigmentation in skin and hair, prevents hair greying, protects the lungs from ozone damage, acts as a coenzyme in the utilization of protein, assists in the formation of red blood cells and enhances the formation of folic acid in the intestine.
Deficiency can result from a poor intake of dietary PABA as well as a poor diet in general so insufficient is made in the body. Deficiency symptoms include eczema, wrinkles, fatigue, irritability, depression, arthritis and bursitis.
Best natural sources of PABA are brewer's yeast, liver, whole grains and eggs. It can also be made by intestinal bacteria.
Vitamin B15 – Pangamic Acid
Very little is known about pangamic acid, although we know it is not a dietary essential as it can be synthesised in the body. It may be involved in blood cholesterol lowering and aiding protein synthesis.
Pangamic acid is present in brown rice, brewer's yeast, brown rice, whole grains, nuts, pumpkin seeds, sunflower seeds and sesame seeds.
Vitamin B17 – Laetrile
Laetrile is also known as amygdalin and although referred to as a vitamin, it is not really one by definition. There is a lot of research into its use as a treatment for types of cancer, although evidence is mixed. Foods high in laetrile include apricots (fresh, canned and dried) and black cherries.
Vitamin C is also known as ascorbic acid and is a water soluble vitamin. It has a number of functional roles including aiding wound healing, aiding the absorption of iron from the intestines and as a powerful antioxidant. Although vitamin C is an important antioxidant, in the presence of certain metal ions and oxygen it could be pro-oxidant.
Vitamin C is a very labile micronutrient and is easily destroyed by oxygen, heat, light, metal ions and increased pH. Deficiency of vitamin C presents as scurvy characterised by bleeding from the mucous membranes, spots, pallor, depression, loss of teeth and oozing wounds.
There is much debate on the requirements of vitamin C, whether these need to be sufficient to prevent scurvy with some reserve, or whether higher levels are more optimal to reduce risk of disease. The reference intake is 40mg per day, but there are claims, with some evidence, that levels much higher than this are beneficial. Much of this pertains to vitamin C's antioxidant ability. Smokers have lower blood vitamin C levels, so should ensure an intake higher than 40mg per day. Vitamin C is found in a wide range of plant foods though, and eating a varied diet will ensure adequate intake.
One area of debate is the proposed use of vitamin C supplementation in preventing the onset or reducing the severity of the common cold. This is far from proven, yet it's almost accepted by many people that you mega dose with vitamin C supplements if you feel a cold coming on. Although mega doses are advocated by some, caution needs to be noted. High doses can cause diarrhoea, indigestion and kidney stones and may also be pro-oxidant in some circumstances.
Vitamin C is a very labile vitamin and is lost through leeching out into water, through high temperatures and food processing. It is only present in small amounts in animal foods, but is widespread in plant foods. Main fruit and vegetable sources are:
- Avocado (½) - 14mg
- Blackberries (15) - 16mg
- Gooseberries (10) - 26mg
- Grapefruit (½) - 27mg
- Lemon (¼) - 20mg
- Mango - 56mg
- Melon, cantaloupe (½) - 54mg
- Melon, honeydew (¼) - 29mg
- Melon, water (¼) - 20mg
- Orange - 93mg
- Pineapple (1 slice) - 31mg
- Raspberries (15) - 18mg
- Strawberries (100g) - 60mg
- Tangerine - 21mg
- Beansprouts (85g) - 16mg
- Peppers, raw (45g) - 45mg
- Tomatoes, raw (150g) - 30mg
- Grapefruit juice (200ml) - 56mg
- Orange juice (200ml) - 70mg
- Pineapple juice (200ml) - 16mg
- Blackcurrant cordial (45ml) - 95mg
- Tomato juice (200ml) - 40mg
- Broccoli, boiled (95g) - 32mg
- Brussel sprouts, boiled (115mg) - 46mg
- Cauliflower, boiled (100g) - 20mg
- Potatoes, boiled (150g) - 14mg
- Chips (250g) - 26g
- Potatoes, baked (140g) - 14mg
- Potatoes, mashed (170g) - 14mg
- Spinach, boiled (130g) - 33mg
- Swede, boiled (120g) - 20mg