Vitamin supplement chart

This chart outlines who would benefit from taking a vitamin supplement and any relevant warnings.

You are more likely to need a supplement if you are pregnant or breast-feeding; have had a recent severe injury or surgery; have a serious infection; are anaemic; if you drink alcohol and/or smoke; or eat a restrictive or unusual diet.

In general, it is best to first consult your GP or a dietitian before taking supplements, especially if you are taking any medication.

The amount of a vitamin supplement that the body absorbs depends on its needs. How much the body absorbs depends on the chemical form of the vitamin and the acidity or alkalinity where absorption occurs in the digestive tract.

Supplement	Who might benefit from a supplement?	Warnings
Vitamin A USL for long-term use: 2300mcg per day	People with skin problems such as acne and psoriasis Those with infections such as measles or peritonitis, which is inflammation of the membrane lining the abdominal cavity (taken together with antibiotics) People with osteoarthritis Those with poor night vision	Avoid if you are taking any vitamin A-derived medications for skin problems, if you are taking oral contraceptives, or if you are pregnant. High doses can cause flaking, itching skin, blurred vision, and headache. Toxic levels can lead to enlarged spleen and liver and joint pain.
Vitamin B1 USL for long-term use: 100mg per day	People with a weakened immune system Regular alcohol drinkers or smokers	No known problems.
Vitamin B2 USL for long-term use: 200mg per day	Vegetarians Athletes Those who suffer regularly from migraine headaches People with skin problems such as acne, eczema, and ulcers Those with carpal tunnel syndrome (tingling and pain in hand and forearm)	High doses may upset the stomach.
Niacin USL for long-term use: 150mg per day	People with high blood cholesterol	Niacin is prescribed at high doses for treating high blood-cholesterol levels. It is best to take niacin with meals to reduce the likelihood of stomach upset. Avoid if you have liver problems or a peptic ulcer. You should check first with your doctor before taking niacin if you have diabetes, gout, gall bladder disease, internal bleeding from weakened arteries, ulcers, low blood pressure, or the eye disorder glaucoma. Doses of 50mg per day can cause flushing, itching, headaches, cramps, and nausea. Very high doses taken over a long period of time can cause liver damage, high levels of glucose in the blood, and irregular heart rhythm (arrhythmia).
Vitamin B6 USL for long-term use: 100mg per day	People who have a poor diet, such as heavy alcohol users, or older people, who may have difficulties absorbing vitamin B6 from food Those sensitive to monosodium glutamate Women taking oral contraceptives People using the asthma medication theophylline or the tuberculosis medication isoniazide Those with high blood levels of homocysteine – taken with vitamins B12 and folate	More than 100mg per day can cause numbness and tingling in fingers and toes. Very high doses taken over a long period of time can cause liver damage and nerve damage. Fortunately, nerve damage is reversible, and diminishes when you discontinue the vitamin. Check first with your doctor if you have intestinal problems, liver disease, an overactive thyroid gland, or sickle-cell disease, or if you are recovering from illness, injury, or surgery. Supplements of this vitamin may lead to kidney stones.
Vitamin B12 USL for long-term use: 3000mcg per day	Vegetarians and vegans Those with problems absorbing it from food People with anaemia Those who have had portions of their intestines removed or bypassed Those with high blood levels of homocysteine – taken with vitamins B6 and folate	No known problems.
Folate USL for long-term use: 400mcg per day	Pregnant women (see Eating for Two) Those with problems absorbing folate from food People with liver disease or on kidney dialysis (see Disorders of the urinary system) Those with high blood levels of homocysteine – taken with vitamins B6 and B12	Can mask a vitamin B₁₂ deficiency. Consult your doctor if you have anaemia. High doses may cause bright yellow urine, fever, shortness of breath, rash, diarrhoea, nausea, loss of appetite, flatulence, and a swollen abdomen, and interfere with the effectiveness of medications for epilepsy.
Vitamin C USL for long-term use: 2000mg per day	Regular drinkers or smokers People with severe burns, fractures, pneumonia, rheumatic fever (in which there is inflammation of the joints and a high body temperature), or tuberculosis Those preparing for surgery	High doses may interfere with absorption of copper and selenium. Consult your doctor if you have kidney problems, kidney stones, gout, sickle-cell disease, or iron-storage disease. High doses can cause nausea and vomiting, flatulence, diarrhoea, abdominal cramps, and headache.
Vitamin D USL for long-term use: 10mcg per day	Those who do not get enough sunlight People who cannot absorb fats from the intestine, such as those with cystic fibrosis Those with a family history of osteoporosis People over the age of 65, who make less vitamin D in their bodies when skin is exposed to sunlight	Consult your doctor if you have epilepsy, cardiovascular disease, persistent diarrhoea, kidney, liver, or pancreas disease, intestinal problems, or the immune disorder sarcoidosis, or if you are planning to become pregnant. High doses can cause nausea and vomiting, diarrhoea or constipation, headache, extreme fatigue, lack of appetite, weight loss, frequent urination, irregular heart rhythm (arrhythmia), and weak bones and muscles. High doses taken over a long period of time can lead to kidney stones and irreversible hardening of tissues. In babies and children, too much vitamin D can lead to retarded growth, rounding of the skull, and learning difficulties.
Vitamin E USL for long-term use: 800mg per day	Pregnant women who smoke, as it can protect their babies from possible harm caused by the mothers’ exposure to cigarette smoke People at risk of Alzheimer’s disease	High doses may cause dizziness, fatigue, headache, abdominal pain, diarrhoea, flu-like symptoms, nausea, and blurred vision; and decrease libido. Avoid for two weeks before and after surgery. Consult your doctor if you are taking blood-thinning (anticoagulant) medications or have anaemia, bleeding or problems with blood-clotting, cystic fibrosis, liver disease, or intestinal problems. High doses can interfere with the absorption of vitamin A and with niacin’s ability to lower high levels of blood cholesterol. High doses may also increase the tendency to bleed and impair the function of white blood cells.
Vitamin K USL for long-term use: not established	Babies, given as an injection at birth to prevent bleeding Women during and after the menopause, to decrease bone loss People with liver disease, jaundice, or problems absorbing nutrients, or with long-term use of aspirin or antibiotic medications	Vitamin K reverses the effects of blood-thinning (anticoagulant) drugs (see The importance of keeping fit). High doses may cause allergic reactions and brain damage in babies.
Multivitamin and mineral No more than manufacturer recommends	Pregnant (see Nutritional Needs of New Mothers) or breast-feeding women Those who are recovering from surgery or severe injury People who have infections, such as HIV Those who are anaemic or have a low red blood cell count (haemoglobin) (see Anaemia and deficiencies) Regular drinkers and smokers People who avoid entire food groups, such as dairy products if lactose-intolerant Those who are following a low-calorie diet or have irregular eating habits and skip meals Older people or anyone with a condition that affects their ability to absorb nutrients Women taking oral contraceptives	Those taking other supplements listed here may get too much of some nutrients. Those taking anti-seizure or blood-thinning (anticoagulant) medications as listed here.