Should I be taking supplements?

This is a question I am often as in my work as a GP.

Some patients come to see me to ask if they can have certain vitamin levels such as iron, B12, vitamin D and folic acid checked because they feel run down or tired.

Others ask for advice about what vitamins they may be lacking if they have removed certain food groups from their diet.

Parents come worried about kids who are ‘fussy eaters’ being deficient in certain vitamins and others are keen to know if there is any evidence to show that taking supplements can help to reduce their risk of developing chronic conditions such as dementia, cancer, heart disease and diabetes

In the post world war 1 era we started to see some food being fortified to try to prevent nutritional deficiencies within the population. The main vitamins added were A, D and B group vitamins. These practices continue today.

Early adverts in America assured us that vitamins would help us live a better life and would help kids grow ‘bigger and stronger.’

The vitamin and supplement industry has grown massively over the last 10-15 years with UK sales in this area hitting £674.6 million in 2009 with the 2 biggest selling areas being multivitamins (£138.6 million) and fish oils (£139.1 million). Revenue from vitamin and nutritional supplements production reached nearly 31 billion dollars in the United States in 2018.

1 in 3 adults in the US and just under 1 in 2 adults in the UK take a vitamin supplement on a daily basis.

With such an increase in supplement use we are seeing ever increasing numbers of products on the shelves with many promising to help prevent cognitive decline and cancer among other things.

Is there any evidence to support this and should we all be taking supplements?

Let’s start with the basics.

Vitamins and minerals are compounds that the body needs to help build, repair and perform everyday functions including supporting a healthy immune system.

It is definitely possible to get ALL of the vitamins and minerals that you need from your diet although there are a few groups of people in whom vitamin supplementation is recommended both in the UK and in the US.

The caveat to that would be that, although you can get vitamin D from food, the vast majority of our vitamin D is produced in our skin when we are exposed to sunlight.

It comes as no surprise that here in the UK most of us do not get enough exposure to sunlight in the autumn and winter months. Public Health England (PHE) have therefore advised that all adults and children voer the age of 1 should be taking a 10 microgram supplement of vitamin D each day throughout autumn and winter.

Other groups of people who are advised to take supplements include:

Women trying to conceive:

If you are thinking about trying for a baby in the near future or have started trying to get pregnant, you should be taking a folic acid supplement to reduce the risk of your baby having a neural tube defect such as spina bifida.

In the UK the recommended dose is 400mcg but if your BMI is over 30, if you or your partner have a neural tube defect, if you have had a previous pregnancy affected by a neural tube defect, if you are diabetic or if you take medication for epilepsy you should be taking a higher dose of 5 milligrams right up until the 12th week of pregnancy.

The Department of Health also recommends you consider taking a vitamin D supplement (10mcg)

You should avoid taking ANY supplements containing Vitamin A (retinol) as too much can be harmful to your baby.

The advice in the US is for women who are capable of becoming pregnant to take 400-800mcg folic acid daily plus 600IU of vitamin D

Pregnant and breast feeding women:

The above advice regarding Vitamin A stands throughout your pregnancy.

In the UK the advice is that pregnant and breast feeding mums should take Vitamin D 10micrograms per day.

Foods high in Vitamin D include oily fish (salmon, mackeral), eggs and red meat.

Many women become deficient in iron during their pregnancy but routine iron supplementation is not recommended by the Department of Health.

Iron rich foods include lean meat, green leafy vegetables, dried fruits and nuts. Some breakfast cereals have iron added.

If your iron level drops during pregnancy your GP or midwife will give you advice on which supplements you need and for how long you need to take them.

The advice in the US is the same as for those women who are capable of getting pregnant to continue their folic acid and vitamin D.

Children aged 6 months to 5 years:

The Department of Health advice is that all children aged 6 months to 5 years are given vitamin supplements containing vitamins A, C and D every day. The supplementation of vitamin A and C is precautionary as many children, especially ‘fussy eaters’ will not get enough of these vitamins in their diet

It is also recommended that breast fed babies be given a daily vitamin D supplement from birth whether or not you are taking a vitamin D supplement yourself.

Formula has added vitamin D so babies drinking more than 500mls of formula a day do not need to have vitamin D supplements.

At risk groups for vitamin D deficiency who should take a vitamin D supplement all year round:

Those who are not often exposed to the sun- for example those who are housebound, those who cover most of their body with clothing and those with very dark skin.

Those who choose to exclude certain food groups from their diets:

Many people choose to omit certain foods from their diet for medical, ethical, cultural reason and on the basis of personal choice.

If you are following a dairy free diet, you need to be careful to make sure you are getting enough fat soluble (A,D E and K) vitamins and look to see where you are getting these in in your diet.

Vegetarians should be mindful of ensuring they include foods high in iron, calcium, vitamin b12 and vitamin D, especially important for children following a vegetarian diet.

A vegan diet can be lacking in calcium, B12, iron, zinc, omega 3 and vitamin D and iodine. A quick  search online can give you some good pointers as to which foods contain these nutrients. It is worth noting that the type of omega 3 found in plant based foods may not have the same benefits as those found in oily fish.

So, what about all the supplements that make up this multi million pound industry?

Is there any evidence to back their claims that they can help prevent dementia, reduce heart disease, prevent or cure arthritis?

Lets look at a few key players:

Glucosamine and chondroitin:

Touted as a helping reduce the pain of arthritis and preventing progression of wear and tear in joints.

Unfortunately, a review of studies carried out on these drugs has shown NO significant benefit and, as such, bodies such as the National Institute for Clinical Evidence (NICE) do not recommend their use.

Omega 3

The best source of omega 3 is found in oily fish but it is also found in walnuts and flaxseeds.

Omega 3 is often sold with the promise if reducing your risk of developing heart disease and dementia.

Supplements can be expensive and there is some concern that the benefits we see when omega 3 is ingested as part of a whole food cannot be replicated by taking a supplements alone.

Some studies on rats have shown some promise in terms of the benefits of omega 3 supplementation.

For example, rats few a diet high in omega 3 have shown increase neurogenesis (development of new brain cells) compared to those fed a diet deplete of omega 3.

In another trial, 2 groups of rats had their spinal cords severed. One group was given omega 3, the other group a placebo. The group given omega 3 demonstrated better movement than the placebo group and their spinal cords had healed more on examination under a microscope.

But, can we extrapolate this evidence to humans?

Sadly, no.

To date there have been no well constructed studies than have demonstrated any benefits from omega 3 supplementation in those who already have early cognitive decline (dementia).

A review of studies totalling several thousand people who have commenced omega 3 before showing any signs of cognitive decline has also failed to show any benefit in terms of prevention of dementia.

What we don’t yet have are any retrospective studies (studies looking back) to see if those who haven’t developed dementia have had a higher intake of omega 3 over the years than those who have shown signs of cognitive decline.

Despite claims made by various companies there is also no evidence to support it’s role in weight loss or cancer prevention.

Calcium

Is Calcium good for our bones?

Large number trials in the 1990’s showed that calcium supplementation did not reduce the risk of sustaining a fracture.

Similarly, for those without osteoporosis the evidence for taking calcium to reduce your risk of bone thinning is weak at best.

For every 100 people taking calcium supplements, 2-3 people per year will prevent themselves form having a fracture. Sounds not too bad doesn’t it? However studies also showed that there was a link between calcium supplements and risk of having a heart attack or stroke. The risk here was small but probably negates any benefit gained by taking calcium supplements in the first place as you would be far better protecting your bone health with weight bearing exercises and considering HRT if you are a post menopausal female.

Multi Vitamin

America and UK’s favourite supplement.

There is no evidence from studies that taking a multi vitamin supplement is any better than a healthy well balanced diet in terms of reducing risk of cancer, dementia or heart disease and nothing to suggest it increases longevity.

A review of multiple studies involving the use of multi vitamins was carried out by researchers in Canada in 2018.

There were looking at the role of multi vitamins in the prevention of cardiovascular disease. (Supplemental vitamins and minerals for CVD prevention and treatment Journal of the American College of cardiology, May 28, 2018) 

The review found that taking the most widely used supplements-multi vitamins, vitamin D, vitamin C and calcium-had no significant effect on the risk of heart related illnessnor did they reduce the risk of death from any cause. 

Interestingly, it found some supplements such as vitamin B3 (niacin) may do more harm than good.

Vitamin D

Vitamin D has been all over the headlines on both sides of the Atlantic for many years now with multiple news items stating concern about widespread Vitamin D deficiency.

There is much debate among scientists in both the UK and America as to how much vitamin D we need.

A meta analysis of multiple randomised control trials looking at how much vitamin D we need for bone health was carried out in 2015 in the US which ultimately backed current guidelines in terms of levels needed for bone health.

This meta analysis omitted studies looking at vitamin D levels needed to reduce cancer risk, dementia, heart disease and auto immune disease as it was felt that they studies that looked at these issues were not of a high enough quality to ne included.

This led to some scientists and nutritionists arguing that the current recommended levels are too low.

There have been no studies carried out to date that have shown a significant reduction in risk of cancer, heart disease, diabetes or auto immune disease and we therefore cannot say with any confidence that taking current recommended levels or higher levels of vitamin D with reduce your risk of developing these conditions.

Vitamin C and Zinc

Sold as a means of preventing contracting the common cold and flu virus.

There is no evidence to support this claim but there are a few small studies that suggest taking vitamin C and Zinc when you have the cold or flu can help speed up the recovery time.

Vitamin infusions

Promoted by celebrities including Adele and Rhiana, vitamin infusions have become and increasingly popular trend.

Intravenous (IV) vitamin infusions is a method if administering vitamins and minerals directly into the blood stream.

Alternative therapy clinics advocate vitamin infusions for a whole range of conditions including cancer, chronic fatigue, asthma, chronic pain and fibromyalgia.

There is no evidence to date that shows any benefit to these infusions and as such we do not use them on the NHS.

But what about taking supplements as an ‘insurance policy?’

Ok, so we have established that outwith ‘at risk’ groups and those who choose to omit certain food groups from their diet, that there is little evidence to back the use of vitamin supplements IF we are consuming a well balanced diet containing a wide variety of fruits, vegetables, animal/plant based proteins and dairy/fortified non dairy equivolents.

If the assumption is that people are lacking essential nutrients in the diet, the focus should be on fixing the diet.

Taking vitamins in isolation or as part of a multi vitamin or vitamin infusion may not provide the same benefits as ingesting them as part of a balanced meal in a food matrix.

This idea is backed by the British Nutrition Foundation who state:

‘The matrix can influence the extent of the nutrients absoprtion both positively and negatively. In a healthy individual, the digestion and absorption of food is finely regulated to release nutrients into the bloodstream from the gut and from the liver. If nutrients bypass this process and enter directly into the bloodstream in high doses, this could potentially cause harm and, to date, the medium and long term effects are unkown.’

To date there has been no robust evidence form human clinical trials showing any positive health benefit. All excess vitamins are simply excreted in the urine.

Many of us feel we struggle for time to plan and prepare our meals and snacks or go through periods when we are less good at ensuring we have a variety of foods in our diet and therefore feel we may be lacking essential nutrients.

What harm is there then is taking a supplement?

Most likely, there is little harm if you are taking a single oral supplement of one vitamin/nutrient or one multi vitamin but it IS well established that some vitamins and minerals can be harmful in excess, especially the fat soluble (A,D, E and K) ones as they are stored in fat rather than the excess being excreted in the urine. This is where my concern about IV infusions lies.

For example, high doses of vitamin A can cause liver and bone damage and high doses of vitamin E can affect the absorption of other vitamins.

In addition, clinics offering these infusions do not have access to your medical records and may not be aware of possible complications.

In addition, paying less attention to what you are taking in in terms of whole foods and ‘balancing’ this up by adding in supplements does not provide other benefits of eating the whole food.

A good example of this can be seen in a person who, either by following a specific diet (eg very low carbohydrate such as keto) or by having a dislike of foods such as fruits, vegetbales and pulses eats a diet lacking in these could be tempted to ‘top up’ on the nutrients they may be missing by taking a multi vitamin. This will not do anything to address other issues such as potential lack of dietry fibre, as well as other issues such as promoting a healthy population of good gut bacteria (gut microbiome) and again cannot really be seen as an adequate substitute for a varied diet.

Others will comment that eating a varied diet is expensive but many stores, for example ALDI and LIDL offer a wide variety of fruit, vegetables, whole grains and pulses at affordable prices and I would argue that cooking a couple of meals out of the weekly ‘super six’ is just as cheap as other meals eaten by the majority of the population. Frozen fruit and veg can be a cheaper alternative and are just as nutrient dense, if not more so, than their fresh counterparts.

So, my advice would be to follow the government guidelines in terms of who evidence supports the need for supplements.

Outwith this, look for cheap, easy ways to get all you need into your diet in tasty, whole foods and consider taking 10mcg of vitamin D daily in the autumn and winter months if you live in the UK.

©AYOSC 2019