Monday, 15 April 2013

Dietary Supplements - do we really need them?

We have all done it of course, popping a multivitamin pill whenever we feel 'run down' or feel that we haven't been eating properly for a while, running ragged, totally stressed or simply unwell. However, a growing number of medical experts are increasingly concerned about members of the public overdosing on dietary supplements (mostly vitamins) convinced that the pills will make them healthier. This relates more specifically to those who adopt dietary supplements as an integral part of their diet. So let's examine this in closer detail to understand and appreciate their concern - so what are dietary supplements?

Definition
Dietary supplements is a generalised term used to cover any substance that is taken to enhance the quality of a person's diet. Traditionally, this has been our old favourite, the good 'ol multivitamin and mineral supplement (or horse tablets as my husband affectionately likes to call it!). Over the years however, the list of dietary supplements has increased to cover things like herbal supplements, protein drinks (muscle-building supplements), fish oils, fibre supplements, probiotics (also as drinks), algae supplements such as spirulina and chlorella (considered as a superfoods), a wide range of herbal supplements and homeopathic supplements. From the consumer's point of view, this is a bewildering array and like many of us, unsuspecting of the potential damage that any of them can cause given that it they are marketed under 'health' foods. So why do we take supplements?
Well, there are very good reasons why supplements should be taken. The main reasons are listed below:
  1. soil depletion - reduced nutrient content of food supply
  2. hybrid crops - provide lower nutrient foods
  3. modern fertilisers - do not supply enough trace elements
  4. modern chemical pesticides & herbicides - low level toxicity of foods and damage soil microbes. Also lowers the nutrition of the crops
  5. long-distance transportation of foods - diminishes nutrient content of foods
  6. food processing - drastically reduces nutrient content of foods eg. flour, rice, dairy produce
  7. pasteurisation & homogenisation processes - drastically reduces bioavailability of calcium, phosphorus and some milk proteins in dairy products
  8. food additives - depletes nutrients
  9. weak digestion & poor eating habits - impairs absorption of foods
  10. stress & modern lifestyles - impairs digestion and uses up more nutrients
  11. infections & illness (chronic & acute) - depletes nutrients and increases nutritional needs
  12. increased use of vaccines & other medicinal drugs - depletes nutrients and requires extra nutrition as the body has to process them
  13. heavy metal pollution of air, water & elsewhere - depletes nutrients and increases their need to stay healthy and robust in order to combat toxicity
  14. medical procedures & surgery - eg. x-rays, surgical procedures can increase stress, strip the system of B-vitamins and possibly zinc
  15. special life situations and health conditions - require extra nutrition eg. birth defects, chronic illness, pregnancy, heavy menstrual bleeding, being vegetarians or vegan, drug addictions....
These and other issues prompt us to take supplements and my work as a practitioner involves advising about good quality brands that have some basis in science and technology with regards to manufacture, quality control and standards of practice. However, many are swayed by cost not realising that cheaper brands are not necessarily good quality and buying online from sources that cannot be verified is a recipe for disaster. So what can one do to ensure safety and efficacy if taking supplements is a necessity? Read my blog post of April 2010 'A Guide to Commercial Supplements' where I make recommendations and suggest brands that I approve of:

http://yaso-shan.blogspot.co.uk/2010/04/a-guide-to-commercial-supplements.html

Additionally of course, one needs to consider the health risks of overdosing. This is a tricky issue as many of the manufacturers nowadays provide 'megadoses' that are infinitely higher that the recommended dose (RDAs, RDIs and MDAs). This is probably more of an issue in the US and other non-European countries since the EU has strict laws and restrictions on the sale and availability of supplements in Europe (including the UK) which do not permit this. Further, there are classification differences where specific laws apply (eg. Traditional Herbal Medicinal Products Directive in the EU whereas supplements are classed as foods in the US). Over the counter (OTC) doses seem to be more determined by market forces rather than nutritional needs which can lead to toxicity through overdosing. Common problems are encountered with taking too much of a particular supplement are highlighted below although these are just a few, selected examples of toxicity and adverse effects (the comprehensive list being too long to mention here!):

Vitamins
A - nausea, blurred vision, dizziness
B6 - nerve damage
C - diarrhoea, nausea, stomach cramps
D - kidney stones (probably due to excessive calcium absorption/deposition)
E
 
Minerals
Iron - increased risk of heart disease
Calcium
Zinc - nausea, diarrhoea, stomach cramps
Magnesium - muscle cramps
Folic Acid - little evidence to suggest that it protects against heart disease by lowering homocysteine
Selenium - hair loss, gastrointestinal upset, fatigue, mild nerve damage

Note: there are issues around bioavailability (how the nutrient is made usefully available to the body) and complex formulas may impact on this eg. zinc competes with iron, which in turn competes with calcium.

There are significant differences in the way supplements are sold in the US (FDA regulation) compared to the UK (EU regulation) namely that in the US, supplements are sold as foods and do not need to prove that they are effective nor indeed list any of the side effects even when ingredients in them are known to cause them.

Can we get optimum nutrition from foods?
Although modern foods are fortified, nutritional needs are still not being met. Why is this? Well, fortification of foods should address any of the issues that surround the stripping of vital nutrients during manufacture and food processing. However, disease states of the western world are still high such as cancer, heart disease (eg. CHD), stroke and hypertension. Whilst appreciating that disease is a complex interplay for many factors outside of food/nutrition, it seems that the concept of 'optimum nutrition' may be an unrealistic one.

Supplements vs Wholefoods
Wholefoods are not processed,
fresh and hopefully locally sourced
to ensure maximum nutrient quality
I have advocated whole foods for as long as I can remember. However, the recent horsemeat scandal in the UK has done more damage than any other incident to dent the public confidence in our foods and food supply chain. In an ideal world it would be good to ensure that foods provide exactly what they are supposed to but given the enormous constraints on food production (as highlighted above), it may be safe to rely on tinned foods and frozens in a bid to guarantee some nutritional quality (foods packed this way are packed at the point of harvesting). It is safe to say however, that overdosing on wholefoods is highly unlikely as one would have to consume vast quantities of a particular food on a daily basis to get anywhere near the kind of doses that supplements offer.

Recommendations
Given the concerns, if you think you should still take dietary supplements, it is best to ascertain your nutritional status. Diagnosis can be done quite simply through a blood or urine test (NHS), hair analysis ie. hair tissue mineral analysis (private), analysis of food diaries (informal or formal) or stool test (NHS). Age, disease, medical procedures, pregnancy, chronic disease and trauma are all special cases and require proper medical supervision for supplementation. Seek advice before any self-medicating! This is particular true for herbal supplements which are unique in their set of considerations:
  1. herbs contain many nutrients and have active constituents that exert specific actions on the body
  2. herbs have a medicinal effect therefore dosing is critical
  3. herbs can interact with food, conventional drugs or other supplements so professional advice is compulsory before self-administration
  4. quality of the herbal supplements can vary - this affects dosing which can therefore vary
  5. a combination of herbal supplements can cause problems especially interactions
  6. good quality herbs/reputable brands are costly putting off those who can't afford it to purchase cheaper, less safe brands of poor quality.
The following are the only situations where high doses are recommended:
  • to balance cellular mineral ratios
  • to counteract & ameliorate specific physical, mental or emotional symptoms
  • to provide precise nutrients in trauma cases
  • to provide precise nutrients for mental development
Other recommendations:
Avoid chelating agents and herbal drinks (eg. acai berry, camu camu) as the latter is often loaded with sugar. Consider children's doses if worried about overdosing and only take supplements for short periods at a time (eg. a vitamin C supplement during winter). But be careful; there is no definitive scientific evidence at present to prove that vitamins or minerals protect or prevent against disease. Always seek proper professional advice from a medical herbalist before taking herbal supplements and if in doubt, stick to wholefoods and follow a balanced and varied diet to mitigate any risk from nutritional deficiencies. Buy locally wherever possible to ensure freshness, limit transportation issues and nutrient depletion.

For further information, please visit www.food.gov.uk or www.nhs.uk or for specific advice and guidance about nutritional matters and/or herbal supplements, please visit www.phytotherapists.org or www.bant.org.uk

2 comments:

  1. That has a great impact on me. It motivated me a lot more to pursue my diet.

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  2. Pleased that you have found the article useful. We could all benefit from reviewing our diet as we age. I am a firm believer in getting the best from our food but alas we cannot guarantee the high quality of fresh foods anymore....

    ReplyDelete