Water-soluble vitamins

What are water-soluble vitamins?

Water-soluble vitamins include B-complex vitamins and vitamin C. They dissolve in water and are not stored by the body. Excess amounts are eliminated in urine so must be replaced every day in our diet to provide a continuous supply.

Water-soluble vitamins are easily destroyed or washed away during food storage and preparation, but following correct procedures in these two areas can minimise this loss. It's best to refrigerate fresh produce, keep milk and grains away from strong light, and use the cooking water from vegetables to prepare gravy or soups.

Generally, water-soluble vitamins are not harmful as the body excretes excess levels in urine.

B-complex vitamins

B-complex vitamins help the body get energy from food, and are involved in functions such as appetite control, vision, healthy skin, a healthy nervous system and red blood cell formation.

B-complex vitamins:

• B1 - Thiamin
• B2 - Riboflavin
• B3 - Niacin
• B5 - Pantothenic acid
• B6 - Pyridoxine
• B12 - Cobalamin
• Biotin
• Folate (folic acid)

Sources

B-complex vitamins are found in a variety of foods:

• Cereal grains
• Meat
• Poultry
• Fish
• Eggs
• Milk
• Beans and peas
• Fresh vegetables

Vitamin B deficiencies

Insufficient levels of vitamin B can cause the following conditions:

Beriberi - due to a lack of thiamin (B1). Symptoms include weight loss, emotional disturbances and weakness or pain in the limbs.

Pellagra - due to a lack of niacin (B3). It can affect the skin, mucous membranes, central nervous system and gastrointestinal system.

Pernicious anaemia - due to a lack of cobalamin (B12). Symptoms include tiredness, palpitations, shortness of breath and dizziness. It can be masked by high doses of folic acid in the diet, which treat the anaemia without treating the B12 deficiency. This can be dangerous because a lack of B12 can eventually lead to neurological damage. B12 deficiency may be a problem in older people when B12 absorption is reduced. Vegans can be at a higher risk of deficiency because of the absence of B12 in plant foods.

If treated at an early stage these deficiencies can be corrected, with most people making a full recovery.

Supplements

Water-soluble vitamins are available as dietary supplements, but a healthy diet will provide sufficient levels of these vitamins. At certain times, such as preconception and early pregnancy, specific folic acid supplements will be required.

High levels of some B vitamins may be harmful, but this is only likely if you take high-dose supplements, and not from natural food sources. For example, high doses of vitamin B6 can cause peripheral neuropathy, resulting in an unstable gait and numbness.

As with all supplements, no more than the dose stated on the package should be taken.

Vitamin C

Vitamin C is needed for normal growth and development, growth and repair of tissues within the body, formation of collagen, cartilage, bones and teeth, and wound healing.

It also helps to protect against infection by enabling white blood cells to break down bacteria, and plays a key role in iron absorption from the intestine.

The recommended intake of vitamin C is 40mg a day, and most people in the UK get sufficient amounts in their diet. Some people believe high doses of vitamin C can protect against colds and other infections, but there’s no strong evidence to support this.

If supplements are taken, don’t exceed 1,000mg a day because any more can cause stomach pain, diarrhoea and flatulence.

Sources of vitamin C are:

• Citrus fruits
• Plantain
• Asparagus
• Broccoli
• Brussels sprouts
• Cabbage
• Peppers
• Tomatoes

Vitamin C deficiency

People who drink alcohol regularly, smoke or are on a restricted diet may have an insufficient intake of vitamin C. Alcohol prevents vitamin C absorption and cigarettes deplete vitamin C levels.

People with wounds, burns, pneumonia or recovering from surgery may need more vitamin C to support the healing process.

A deficiency can result in scurvy. This causes muscle weakness, joint pain and problems with wound healing. It can also lead to loose teeth, bleeding and swollen gums, easily bruised skin and fatigue, and sometimes depression. Scurvy can be treated with vitamin C supplements prescribed by a doctor.