Choosing supplements with your doctor

Why choose supplements with a doctor

A supplement works best when it answers a known need, and a short conversation with a doctor is the quickest way to find out whether you have one. In the UK, food supplements are sold as food, so they do not go through the testing for safety and effect that a medicine needs before it reaches a shelf [1].

The evidence for using supplements to prevent long-term disease in healthy adults is thin. The US Preventive Services Task Force found too little evidence to say whether multivitamins, or most single or paired nutrients, help prevent heart disease or cancer [2]. It recommends against beta carotene and vitamin E for that purpose, because beta carotene raised the risk of lung cancer in people who smoke or have worked with asbestos, and vitamin E showed no net benefit [2].

Where UK advice recommends a supplement

A few supplements carry clear UK advice. Everyone should consider 10 micrograms of vitamin D a day in autumn and winter, and people whose skin gets little sun, such as those who always cover up outdoors or live in a care home, are advised to take it all year [3].

Anyone who may become pregnant is advised to take 400 micrograms of folic acid a day before trying for a baby and for the first 12 weeks of pregnancy, because it helps prevent neural tube defects [4].

Beyond these, a supplement is usually the treatment for a deficiency that a blood test has found, given at a dose and for a time a doctor sets with you.

Who should take extra care

Supplements can cause harm, most often through interactions with medicines. The MHRA has warned that St John’s wort can interact with every antiepileptic medicine [5], and reports from the public revealed its interaction with hormonal contraceptives [6].

Speak to a doctor before starting a supplement if any of these apply to you.

• You take a prescription medicine, especially a blood thinner or an antiepileptic
• You are pregnant or planning a pregnancy
• You have kidney or liver disease, or you are due to have surgery
• You smoke, and the product contains beta carotene [2]
• You are considering a product sold for weight loss or sexual performance

Products that carry the most risk

Some products sold as supplements contain hidden drugs. A review of US regulator warnings from 2007 to 2016 identified 776 supplements with undeclared drug ingredients, most of them sold for sexual enhancement or weight loss [7]. Buying from a supplier you know, and showing your doctor what you take, lowers the chance of an unpleasant surprise.

Benefits and limitations

The benefit of a supplement chosen for a reason can be real. Correcting a proven deficiency treats its cause, and folic acid before conception helps protect a baby’s developing spine and brain [4].

Higher doses are rarely better. A trial of vitamin D in 25,871 healthy older adults found it did not lower the rate of cancer or major heart events over a median of 5.3 years [8]. Taking several products at once also raises the chance of doubling up on the same nutrient.

How you prepare, and questions to ask your doctor

Bring every product you take, or clear photographs of the labels, with the dose and how often you take it. A doctor can then check each one against your medicines and your health, and decide whether a blood test would answer the question better than a guess.

• Do I have a reason to take this, or a deficiency we can test for?
• Could it interact with anything I already take?
• What dose is safe for me, and for how long?
• How will we know whether it is helping, and when should I stop?
• Would a licensed medicine be a better choice for this problem?

If you think a supplement has caused a problem

Stop taking the product and tell a doctor or pharmacist. You can also report a suspected side effect of a herbal medicine yourself through the MHRA’s Yellow Card scheme, listing everything else you take [6].

If you have swelling of the face or throat, or severe difficulty breathing, after taking any product, call 999 in the UK or the local emergency number.

How The Wellness can help

A GP appointment gives you time to go through what you take and whether you still need it, and to leave with a clear plan. If a blood test would settle the question, the Core Wellness blood test includes vitamin D and ferritin among its markers, and a doctor explains the results with you.

Every doctor is GMC registered, and samples go to accredited laboratories. Our clinics are on Baker Street in Marylebone and Eccleston Street in Belgravia, and once you and your doctor have decided what you need, our shop is there when you want it.