Dietary Supplements


  • Beware overdosing on fat-soluble vitamins (D, as an example), as these accumulate in the body and may introduce health problems.
  • Consider your diet, and whether you actually need supplements (in general, and on any given day).
  • Pay attention to your body for symptoms which might tell you you’re deficient (fatigue, etc) or have blood tests to find particular vitamins you need to supplement.
  • Beware Trojan horses (sugar and salt in effervescent tablets and cereals, for example).
  • Mitigate the need for supplements with a varied and healthy diet.

My Conclusion

Supplements have a place in my diet, but I’m going to stop popping them through habit and listen to my body and watch my diet to use them only when I think there’s a legitimate reason to boost a deficiency.

Dietary Supplements – Overview

As with all posts in this blog, my objective is to thoroughly (as thoroughly as time permits) research something, and jot down what I’ve learnt. The idea is that explaining something is the best way to learn. The subjects I choose to research, so far, are not driven by academic interest, but by an immediate motivation to challenge my mental model of that subject.

In this instance my immediate motivation is driven by two recent events:

  1. I’ve just received the results from a gene and microbiome test which have highlighted a couple of potential dietary risks I need to mitigate; and,
  2. I need to re-up on my supplement stock, which has got me thinking about the expense and whether it’s worth it.

Specifically, as a combination of my genetic make up and microbiome composition, I have a predisposition to lower than average iron and b-vitamin (specifically b6) levels.

As well as this, I have a genetic predisposition to obesity and stroke, which means that I need to watch my lipid profile (HDL (good) / LDL (bad) cholesterol ratio).

Nothing scary here, but it does give me specific reasons to think about getting enough b-vitamins and Omega 3’s into me.

The obvious answer is to dose up on broad spectrum multi-vitamins, but is this really the right approach? Do they even increase vitamin concentrations in the body; are there any risks; and is it all just marketing hype from the £[insert large number] multi-vitamin industry?

My usual process for investigating something like this is to review the health claims and potential risks and try to come to a conclusion about the validity of them to establish a balanced view. In this case though, the claims and risks just weren’t all that far-fetched or interesting, so I’ll quickly summarise below.

Claimed benefits and concerns


  • dietary supplements fill gaps in a non-optimal diet,
  • particularly when there are circumstantial reasons that there might be increased demand or deficiency (pregnancy, for example);


  • dietary supplements can ‘smuggle in’ unwanted calories or nutrients (sodium in the case of effervescent tablets, sugar in the case of vitamin-enhanced cereals, etc);
  • it is possible to overdose on vitamins, which can introduce health risks;
  • vitamins abstracted from their food source may not be adopted in the body as well as when consumed in whole foods;

In my previous analysis of the facts around cold therapies and consumption of apple cider vinegar it was easy to sweep aside the risks and focus on the health claims for their veracity.

In the case of dietary supplements the benefits can more easily be swept aside on the basis that it’s pretty uncontroversial that consuming supplements has a good shot of addressing deficiencies of those vitamins in the body. I’m much more interested in the risks, because I fear there’s a real chance I might be doing myself some harm.

Of these concerns, I’ll focus on the ‘Trojan horse’ argument, and the overdose risk. The efficacy concern does have a financial penalty (wasting money on supplements), but I’m much more concerned about health risks.

My current habits

First let’s look at my current habits.

It’s tough to define the grey area between supplements and drugs. A great example is caffeine, which is my fist routine ‘dose’ of the day. I don’t habitually take aspirin, nicotine, or anything like that, so it’s the only ‘supplement’ that sits in the grey area.

  • Caffeine. I estimate that I deliver 300 mg of caffeine into myself via coffee per day.
  • Gelatin. Approximately 3 heaped tbsps per week, so 6g on average per day plus ~ 2g in the gelatin coating of the other supplements.
  • Astaxanthin. Approx. 6mg/day via a dedicated cap.
  • Fish Oil. (cod liver). Approx. 450 mg of Omega 3 fatty acids via fish oil caps.
  • Multi vitamin. Approx 1.5 tablets per day delivering broad spectrum multivitamins.
  • Neuro focus plus. Another multi vitamin, but with a focus on ‘nootropics’ (brain enhancers, like turmeric as well as standard vitamins (mostly b vitamins).
  • Krill oil. More Omega 3s (190 mg) plus Asthaxanthin (0.2 mg).

Overdose risks

Across all of these, the following dramatically exceed the RDA (as specified by the NHS).

  1. Folic Acid. Folic acid is water soluble, and so will not accumulate in the body. Excess folic acid will be expelled in urine.
  2. B Vitamins (B3 (Niacin), B2 (Riboflavin), B12 & B6). As above, unconcerned given that these are all water soluble. Also, I have a genetic predisposition to reduced B vitamin uptake.
  3. Vitamin C. Also water soluble.
  4. Vitamin D. Fat soluble, so accumulates in the body, which can, over a long enough period, lead to calcium build up and kidney problems.
  5. Vitamin E. As above, vitamin E is fat soluble and so accumulates in the body, although I can’t find any specific risks associated with vitamin E accumulation.
  6. Zinc. Zinc is water soluble.

So, across all of the vitamins delivered by all of my supplements, vitamin D is the only one that I consider to have the potential for introducing health risks.

Given that I will be getting Vitamin D from sunlight (dose unknown, but the estimate is that most people will get all they need from 10 minutes outdoors from March-September in the UK) and from food (fish, red meat, eggs – all of which I consume a lot of), I think I need to reduce my Vitamin D supplementation.

As for Omega 3 fatty acids, there aren’t really any RDAs. There is however a way to test for your lipid profile by using blood tests (I use Thriva). In my testing I can see that my lipid profile is slightly the wrong side of the line. I definitely need to address this by reducing my ‘bad fat’ intake, but I’m also focusing on increasing my ‘good fat’ to balance the two out. As my profile falls back into line I might consider reducing my intake of Omega 3 supplements.

Trojan Horses

Aside from some sunflower oil (which I would prefer to keep out of my diet) at maybe 1 ml/day, and some unknown trace ingredients which sounds as though they might be worth some more investigation (Ammonium Hydroxide?), my cocktail of supplements doesn’t contain too many stowaways.

But are they necessary, given my diet?

Given the above, I’m relieved that I’m probably not harming my health. But am I hurting my finances unnecessarily? The guidance for most vitamins on the NHS website is that most people will be able to get everything they need from their diet, so why bother with supplements?

Let’s consider Kale. A 100 gram serving (just under half a bag of pre-prepared kale) contains way in excess of RDA of Vitamins A (which is fat soluble, so a serving will contain a couple of day’s worth) and C.

A small rib eye steak will get me most of the way on my b vitamin requirements, along with the kale, and will also give me plenty of protein and some collagen.

Throw in a bunch of almonds, an egg, and maybe some spinach, and it’s not hard to cover off magnesium, iron, calcium, Vitamin D and other goodies like folic acid.

The above is representative of my diet on a good day, but they’re not all good days. On the bad days it’s clear that I will need supplements to get me up to my RDAs.

As for the question of whether the vitamins actually make it through to your body and as they would if consumed in whole foods, I certainly can’t find any strong evidence either way, which is surprising. Given that the NHS do recommend supplements as an effective way to address deficiencies, and they’re usually pretty science-driven, I’m going to behave as though they do deliver some vitamins to the body.


My takeaway from this research is that supplements should be used only when there is a reason to take them. In some people it will be factors like pregnancy (which requires more folic acid than can easily be delivered through diet) or lack of sunshine (which makes it harder to get enough vitamin D), or veganism; but, most likely, simply because they’ve had a couple of days of poor diet. This is definitely the case with me from time to time.

In my specific case, the day after a night of boozing will be one to watch. Alcohol is a diuretic, and so will flush water soluble vitamins from the body, so I’m going to be mindful to supplement my b vitamins when I have a hang over.

I will change my habits from now on so that I pause to think about how my diet is going before popping the supplements. For example, I know I’m having some salmon tonight, so the fish oil (Omega 3s) and Asthaxanthin are staying in the bottles for today.

I’m also certainly going to cut back on the Vitamin D until the winter properly kicks in.