Should I Be Taking Supplements?

Should I take supplements?Probably one of the commonest questions I get asked is whether or not people should take supplements. The idea certainly seems appealing, that by taking these little pills, you can almost ‘insure’ yourself against perhaps a less-than-perfect lifestyle. On the opposite side of the argument, we are told that we don’t need to supplement as long as we eat a well-balanced diet. So what’s going on?

Firstly, it is really important to emphasise that every individual is unique, and therefore the decision whether or not you need a supplement is not something that you can work out from a blog post. The most I can do here is to give you some information to help you decide (alongside your healthcare professional if needed), where you stand on this matter.

Nutritional depletion

Unfortunately, in today’s frantic world where meals are often grabbed on-the-go, it can be pretty challenging to make sure that you are getting enough of all of your nutrients over the course of a day or week. There are lots of reasons for this,

  • You really need to be eating a very well balanced and thoughtfully considered diet to have a good chance of including all the micronutrients you require. This is by no means impossible, but it does mean a diet jam-packed full of high nutrient density foods: things like fresh fruit & vegetables, nuts, seeds, good fats, legumes, oily fish, organic eggs and high-quality, grass-fed meat. There really isn’t much space in terms of energy consumption left for ‘junk’ (sugar, processed foods, alcohol) (1).
  • We no longer eat food fresh from the ground. As hunter-gatherers, or even as farmers, we would be eating food very soon after it was picked. The longer fresh food is stored, the more depleted of certain phytonutrients and vitamins it gets. Food picked weeks ago and transported halfway across the world may still look fresh, but has a very different nutrient profile to something picked and eaten the same day.
  • Our soils have become deficient in certain minerals due to centuries of intensive farming practices. Also, UK soils are naturally deficient in certain minerals, such as selenium. This, alongside selective breeding of crops for yield by weight has led to lower concentrations of nutrients in foods, particularly vegetables, over time. That means that most carrots you eat today are not as nutrient dense as the carrots your grandmother ate. (2)
  • Food production and animal and plant breeding methods make commercially grown food vastly different to the diet we evolved to eat – which was predominantly wild food. Although I do not sign up to the Paleo ideal as such, the principle that we haven’t ‘caught up’ yet to the environment that we now live in is certainly true. Wild food has a tougher life – it is not cosseted with herbicides to fight off competition, pesticides to fight off predators or fertilisers to make growing easy. In essence, it has to work harder to exist, and therefore often has a higher phytonutrient profile which are the natural compounds that protect a plant as it grows. Animals which would originally have eaten a grass-based diet, including many other meadow plants, are now kept in barns and given grains (which changes their fat profile) (3). Even fish haven’t escaped intensive farming practices (causing some farmed ‘oily’ fish to have minimal beneficial omega-3 content) (4). The animals and plants we now eat can therefore have fewer nutrients than were available to our ancestors.
  • Cooking (especially boiling), can leach vitamins and phytonutrients out, depleting their nutritional profile even more.
  • Factory food processing can severely deplete nutrients, to the point where there is basically no benefit to the food beyond providing you with calories. Yet this is unfortunately the type of food that many rely on. This can lead to the paradox of obesity and malnutrition going hand-in-hand: a diet high in processed, high-sugar, high-calorie foods has an excess of energy, but a huge deficit in nutrition.

Given all of this, it seems like it might be quite difficult to get enough of the right nutrition into our bodies, so perhaps you’re thinking a multivitamin would be a good idea? There is a but, however.

More is not always more

Unfortunately, it is not so simple as just adding a couple of multivitamins into your diet and job done. I know the message you’re getting here is a bit confusing then, which reflects the confusion in the media too. For example, one day vitamin D is a panacea for all ill-health, the next it causes some worrying disease. The problem is that nutrition research is very difficult to do reliably, and researchers often look at nutrient supplements individually as if they were drugs. It is hard to measure the effect of nutrients working together as a ‘team’. For example, spinach is a brilliantly health food, but if all you ate was spinach, you would get poorly and die. You need to eat a balanced amount of all the nutrients to maintain optimum health.

A word of warning. Research has also shown that in certain circumstances, nutritional supplements can, in fact, be dangerous. Of course, preventing or treating a serious deficiency is very important, but if someone has a less severe deficiency (a “subclinical” deficiency), there is really not much known about how this should be treated, Taking supplements, particularly at high doses, can cause immediate side effects (such as tummy upsets) (5), but more worrying are the long-term effects. These can range from kidney stones (6) to worsening pre-existing medical problems (5), even potentially increasing the risk of cancer (8), infections (9) or death (10), amongst many more reported effects. So, without wanting to cause alarm, the message is that there needs to be a degree of caution when taking supplements, particularly single supplements at high doses. More is definitely not always better, especially if you are already getting plenty in your diet. Other factors to consider before taking a supplement include;
  • Although we have a pretty good idea about how much of each nutrient we need to prevent a serious deficiency, we do not know enough yet about what ‘optimal’ levels of nutrients are, so therefore how can we know what optimal supplement doses are? Even the recommended nutrient intake values published by the government are often based on educated best guesses.
  • Everybody needs and metabolises different amounts of each nutrient. Therefore a one-size-fits-all multivitamin is unlikely to be optimum for anyone.
  • We are not sure of the ideal ratios of nutrients to take together. For example, taking zinc can make you copper deficient, so should you take them together, and at what doses? There needs to be more research to make this information available.
  • We are now starting to understand the very important role that genetic variation has on how we absorb, use and excrete individual nutrients (11). Whereas current recommendations target the majority of the population to prevent nutritional deficiencies, using a more personalized approach based on an individual’s genome (their unique DNA code) would allow much more targeted recommendations. This is still a pretty novel concept, but we may find that it becomes increasingly more mainstream in the future.


When you go to the doctor and get a prescription, you know that the pill you take is what it says it is. This is because medicines are a heavily regulated product, and undergo years of testing before they are released to patients. Unfortunately, supplements do not have the same level of controls applied to them, so it is very difficult to know exactly what you are buying. These are some of the possibilities when you buy supplements over-the-counter;

  • The form that the nutrient is prepared in may mean that it is absorbed poorly by the body.
  • The dose on the label may not match the dose in the pill
  • The raw materials (such as fish oil supplements, or herbs) may not be tested or processed to remove contaminants (such as mercury, PCBs, or lead)
  • The pill may contain other ingredients than those listed on the packaging
  • The manufacturing process may have poor quality control processes, leading to unreliable quality between batches.
  • Be cautious about too-good-to-be-true marketing claims! They most probably are…
So, whilst I do not endorse or condemn any supplement manufacturers, I would urge you to be cautious if you chose to buy and take supplements. As with the food you eat, try to get supplements from a reputable firm that is happy to tell you about its quality control procedures. Guidance from a healthcare practitioner can be useful to help you navigate which product may be best for you.

Special circumstances

Sometimes, you will be diagnosed with a specific nutrient deficiency, or be at risk of one, such as anaemia. In this instance, it would be important both to try to understand the root cause of the deficiency (in partnership with a health professional), as well as working towards improving it through careful nutritional changes and/or supplements.

Likewise, if you are trying to have a baby, or are pregnant, it is recommended that you should be regularly taking at least a folate and vitamin D supplement. Take a look at this page for further information;

So what is the bottom line?

  1. Consider seeking assessment from a qualified nutrition or healthcare professional before taking a supplement, to work out whether you really need one. It is almost always better to be targeted, and only take what your body requires. Be wary of single nutrient, high dose supplements, particularly if you are taking them for a prolonged time.
  2. Getting a widely varied, great quality diet should be your primary focus. This is the best way to get all the nutrients your body needs, in forms that it can recognise and use, alongside lots of beneficial phytonutrients too. Sometimes it’s thought that it could be these phytonutrients which give more health benefit than the vitamins themselves! It is also very difficult to ‘overdose’ yourself with nutrients from food.
  3. You could try using a food diary app that calculates your nutrient consumption as well as your total calories, to give you an idea of where you might want to make some tweaks.
  4. Eating your food as fresh, minimally processed and lightly cooked as possible to boost nutrient content without adding any extra calories.
  5. Consider growing your own to make sure that you can cut down the time to consumption as much as possible – this can be a great money saver on organic veggies too.
  6. If you are considering becoming, or already are pregnant, do make sure that you check out the information on antenatal supplements.
  7. When choosing supplements, go for the highest quality you can find. Ask for advice if you are unsure about which brands to trust.

The most important thing to take away is that choosing to take, or not take, supplements is very much an individual, personal choice. I hope that after reading this article you feel armed with a little bit more information to take away, to help you make your own decisions, in collaboration with a healthcare or nutritional practitioner if you want some more support.

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(1) NDL/FNIC food composition database home page (2011) Available at: (Accessed: 2 December 2015).

(2) Davis, D.R. (2009) ‘Declining fruit and vegetable nutrient composition: What is the evidence?’, HortScience, 44(1), pp. 15–19.

(3) Średnicka-Tober, D., Barański, M., Seal, C., Sanderson, R., Benbrook, C. and Steinshamn, H. (2016) ‘Composition differences between organic and conventional meat: A systematic literature review and meta-analysis’, British Journal of Nutrition, 115(06), pp. 994–1011.

(4) Weaver, K.L., Ivester, P., Chilton, J.A., Wilson, M.D., Pandey, P. and Chilton, F.H. (2008) ‘The content of favorable and unfavorable polyunsaturated fatty acids found in commonly eaten fish’, Journal of the American Dietetic Association, 108(7), pp. 1178–1185.

(5) Pazirandeh, S., Burns, D. and Lo, C. (2014) Overview of water-soluble vitamins, UpToDate. Available at: (Accessed: 14 October 2015).

(6) Nasr, S.H., Kashtanova, Y., Levchuk, V. and Markowitz, G.S. (2006) ‘Secondary oxalosis due to excess vitamin C intake’, Kidney International, 70(10), pp. 1672–1672.

(8) Lippman, S.M., Klein, E.A., Goodman, P.J., Lucia, M.S., Thompson, I.M. and Ford, L.G. (2009) ‘Effect of Selenium and vitamin E on risk of prostate cancer and other cancers’, JAMA, 301(1), p. 39.

(9) Graat, J.M., Schouten, E.G. and Kok, F.J. (2002) ‘Effect of Daily Vitamin E and Multivitamin-Mineral Supplementation on Acute Respiratory Tract Infections in Elderly Persons’, JAMA, 288(6), p. 715.

(10) Miller, E.R., Pastor-Barriuso, R., Dalal, D., Riemersma, R., Appel, L. and Guallar, E. (2005) ‘Meta-Analysis: High-Dosage Vitamin E Supplementation May Increase All-Cause Mortality’, Annals of Internal Medicine, 142(1), p. 37. doi: 10.7326/0003-4819-142-1-200501040-00110.

 (11) Stover, P. (2006) ‘xInfluence of human genetic variation on nutritional requirements’, Am J Clin Nutr, 83(2), pp. 4365–4425.





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