I eat healthily – why do I need a supplement?

Why you need a supplement even if you eat healthily

The short answer is that there is a big difference between adequate nutrition and optimum nutrition.

Most of the food we eat will adequately support life.  But it does not necessarily sustain ideal health. Witness the latest alarming data (2015) from the UK’s Office for National Statistics (ONS) which shows that life expectancy is increasing, but healthy life expectancy is not.

Even people in the upper income levels face, on average, living the last 8 years of their life in poor health, and being reliant on an increasing array of medicines and medical interventions.

People in the lowest economic levels can face 12 of their last years in ill health! [see data here]

It must not be, and doesn’t have to be, like this.

Your diet is probably sub-optimal even if not outright deficient

National surveys show that many people are deficient in individual vitamins and minerals. [see some extracts from a recent UK survey here] However, that is not – in our opinion – the real reason to consider a supplement.

Because most of these people do NOT eat a well-balanced diet.

Assuming you, however, do have a healthy lifestyle and eat a really well balanced daily diet, you probably can get almost all of your Recommended Daily Allowances (RDAs) of vitamins and minerals, from food. (The exception probably being vitamin D in the winter in the northern hemisphere.)

So you are unlikely to be seriously deficient in any particular vitamin or mineral as measured against RDAs. (We will use the term RDA although this is often now referred to on labels as RNI – Reference Nutritional Intake.)

RDAs are only the level you need to prevent deficiency diseases

BUT – and it’s a big but – these RDAs are calculated on the level you need to prevent overt deficiency diseases. The RDA for vitamin C prevents scurvy and the RDA for vitamin D prevents rickets. But that is a low threshold.

Whether the RDAs are enough to sustain ideal long-term health is entirely another matter.

Vitamin C and vitamin D are good examples. The UK RDA for Vitamin C is 80mg a day. Extensive evidence (reviewed later) shows that an optimum level of 500mg brings major health benefits, but they are not found at the minimal RDA level.

The UK RDA for Vitamin D is just 5 mcg – whereas current university researchers in the field are recommending a supplement of between 25 mcg and 50 mcg a day in the winter.

A level of 5 mcg a day might prevent immediate disease – but the higher optimum levels have been shown to confer major long term benefits such as a reduction in the risk of bone fractures, some cancers and dementia.

In terms of optimum health, we seemingly set our sights too low. We are, for example, urged to eat 5 portions of fruits and vegetables a day. The average is less than 3. The American Cancer Society recommends 9 portions a day.

Your health is determined by more than just vitamins and minerals

An even more important point is that vitamins and minerals are far from the only nutrients that we need for optimum health.

Research shows that nutrients like Omega 3, curcumin, lycopene, lutein, betaine, Co Q10, soy isoflavones and the polyphenols and flavonoids in fruits, green vegetables or green tea are just as important for health as vitamins and minerals – but no RDA has yet been established for them.

To take an example, although there is not yet an RDA for Omega 3, we are advised to eat 2-4 portions of oily fish a week, which would average 1,000 mg a day. The current average intake is 142 mg a day.

A far better criterion for assessing how foods and supplements really impact on long term health is this:

Will they prevent, reduce or slow the six main reasons why health normally deteriorates as we get older?

Those six reasons are:

  1. Damage accumulates to DNA
  2. Inflammation builds up in body tissues
  3. The immune system becomes less effective
  4. Mistakes/mutations happen in the billions of new cells we make each day
  5. Protective genes may be ‘turned off’ and damaging genes may be expressed or ‘turned on’
  6. Tissues become ‘glycated’ or ‘sugar coated’ and cell function is impaired

These six problems – or normally a combination of them – underlie all the killer diseases like heart disease, stroke, cancer, Alzheimer’s and diabetes.

Although these illnesses are often termed ‘age related’ diseases, the term is misleading. These illnesses are not so much due to the passing of the years, but rather to the accumulated damage to DNA and tissue caused by excess free radicals, inflammation, errors in cell renewal, decline in immune function, and adverse gene expression.

Ageing is scientifically defined as:

‘the progressive accumulation of damage to an organism over time leading to disease and death’

If you halt or slow cumulative damage, you will live longer and in good health

Some evidence for this assertion goes back to the ONS statistics quoted earlier. Leaving aside the unfairness of the inequalities involved, in economically deprived areas the average person lives 10 to 12 years in poor health.

In the economically most advantaged areas the years of poor health are reduced to 8  – mostly because such people can generally afford to eat better foods and adopt a healthier lifestyle. Moreover, such people are more likely to educate themselves on health.

But even 8 years in sub-optimal health is neither acceptable nor necessary.

We now have research to show that achieving a long, healthy life expectancy needs a combination of a wide range of nutrients at optimal levels – well beyond just meeting the RDA for vitamins and minerals. (And supported, of course, by regular exercise/physical activity.)

Whereas conventional pharmaceutical medicine is focused on treating the symptoms of age-related disease when it has surfaced, ‘nutraceutical’ science is focusing on prevention through optimal levels of food and nutrition.

Prevention is far better than cure – the case for optimum nutrition

Prevention has to start early – because diseases like coronary heart disease, cancer and Alzheimer’s do not occur suddenly, even though they may seem to. Most take 15-20 years to develop to the point they are clinically noticeable.

Dr Robert Heaney is one of the world’s leading vitamin D researchers.  In The American Journal of Clinical Nutrition he talks about the fallacy of relying on RDAs and the serious consequences of taking less than the optimal amounts of nutrients for health:

“because the current [vitamin] recommendations are based on the prevention of deficiency diseases only, they can no longer be said to be biologically defensible.”

I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and Minerals
Read the whole book online here

The case for optimum nutritional levels, rather than minimum RDA levels, was set out clearly by Dr Paul Clayton in his seminal book Health Defence. Dr Clayton is a former president of the Forum on Food and Health at the Royal Society of Medicine.

His conviction is that good health can be maintained, and ageing slowed down, by the right foods, supported by a careful combination of supplements. These should reproduce the range and levels of nutrients found in the diets of the longest-lived people in the healthiest societies. There are pockets of ultra-long-lived populations around the world called ‘Blue Zones’ and his recommendation draws lessons from them.

The secret of optimising nutrition

As mentioned previously, there is a critical difference between a nutritional intake that simply prevents deficiency and an optimal intake that significantly cuts the risk of ‘age related’ disease by counteracting the root causes of long term illness.

A supplement is never a replacement for eating healthy food. But without extra support from a well-designed supplement, very few people in a modern society – even if they adopt a healthy lifestyle – will get the OPTIMUM intake of all the proven health defensive nutrients on a continuous DAILY basis.

Moreover, the definition of a healthy lifestyle is pretty challenging. It includes:

  • sleeping 8 hours a day
  • low stress
  • regular work, activity or exercise outdoors in unpolluted air
  • and eating foods that are fresh, largely organic and grown locally in nutrient and mineral-rich soil

Not many of us can live up to that standard.

But before we examine what an ideal supplement might look like, let’s answer the three common objections to them.

Common objections to taking supplements

1. We didn’t evolve needing vitamin supplements

True – but back then we were highly active and eating an estimated 4,000 calories a day – largely plant based. Now – unless we risk weight gain and obesity – it is nearer 2,000 calories a day. And less food means less nutrient content as well as fewer calories!

In addition, a good proportion of what we eat nowadays is in the form of processed foods which are lower in nutritional quality.

The unhealthy Omega 6 to Omega 3 balance

In particular most of us have an unhealthy balance of Omega 6 to Omega 3 oils.

Fats such as palm oil, corn oil, butter substitutes and sunflower oil in processed foods, snack foods, fast foods, mayonnaise, cakes, biscuits and pastries all contain Omega 6. This accounts for the fact that we now have an intake ratio of Omega 6 oils to Omega 3 oils which is FAR too high – about 17:1 when it should be nearly 1:1.

Excess Omega 6 is strongly linked to inflammation, which in turn is a key driver of heart disease, stroke, diabetes and some cancers.

In contrast Omega 3 oil is an anti-inflammatory, but the average diet is sub-optimal in Omega 3, as the best source is oily fish – experts recommend 2 – 4 portions a week. The average is less than one.

The lower nutritional value of even fresh foods

Even the fresh foods we buy can be lower in nutritional value than they were as little as 40 years ago. Intensive and single-crop (monocrop) farming have depleted mineral levels in the soil and lengthy long-distance supply chains have made the problem worse.

A survey in Scientific American confirms that …

“… crops grown decades ago were much richer in vitamins and minerals than the varieties most of us get today”

It’s not a scare story. A University of Texas study published in December 2004 in the Journal of the American College of Nutrition showed …

“… reliable declines in the amount of protein, calcium, phosphorus, iron, riboflavin and vitamin C, magnesium, zinc and vitamins B6 and E over the past half century in 43 different vegetables and fruits”

The findings are confirmed by many other surveys.

It’s not just plant foods. Intensive farming of animals for meat means, for example, that they need to be treated with antibiotics. Not only is that causing dangerous antibiotic resistance, but methane output in such cattle is double the normal amount – and a serious contributor to global warming.

Increased life expectancy and other modern lifestyle factors

Ironically, increases in life expectancy also increase the need for extra nutrition – because we become less able to absorb nutrients from food as we age.

Other aspects of modern life have increased the need for extra micronutrient intake:

  • For city dwellers exposure to pollution is inevitable. Pollutants like nitric oxide and sulphur dioxide are free radicals which are known to damage DNA and body tissue. Hence the thousands of premature deaths that are directly linked to pollution. Additionally pollution cuts sunlight which reduces vitamin D production in the skin.
  • Eating on the run or while travelling makes consistent ideal food choices difficult
  • The contraceptive pill decreases blood levels of zinc, magnesium and folic acid
  • Use of statins lowers levels of vitamin D and CoQ10 in the body
  • Alcohol consumption reduces levels of folic acid, vitamin B6, vitamin C, zinc, and selenium
  • Antibiotics deplete healthy bacteria in the gut, which in turn depletes levels of B vitamins and inhibits the production of vitamin K
  • Prolonged stress – whether in the workplace, commuting or just coping with the pace of life – puts additional demands on our nutritional status. In particular, stress depletes Omega 3, vitamin D, vitamin C and magnesium which is vital for normal heart regulation.

So, yes people did evolve and live without supplements, but the nutritional demands on us have now changed and increased.

2. My doctor thinks vitamin supplements are a waste of time and money

Doctors know a lot about drugs – but generally a lot less about nutrition!

The National Institutes of Health is the biomedical research facility of the United States Department of Health. They surveyed the amount of nutritional education in US medical schools.

The average was less than 20 hours of instruction in 4 years of medical school ie. just 20 hours over a typical 40,000 hours of total training to be fully qualified. The same is true in the UK.

Compounding the problem is that most practising doctors completed their minimal nutrition training years or even decades ago, and have rarely updated themselves since then. As a researcher dryly noted: “The receptionist often knows more than the doctor!”

I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and MineralsThe demands on doctors are such that they rarely have time to explore or practise preventative medicine. The doctor’s model is generally a pharmaceutical one – they are presented with an illness when it has already progressed to be evident – and the default position is to treat it, or often just the symptoms, with a drug.

Doctors tend to favour drugs, which are fast-acting, over nutrition which takes time to have an effect. Physicians are also inevitably influenced by the pharmaceutical industry and ‘Big Pharma’s’ business model is to encourage the prescription of patented, high margin drugs, not foods or nutritional supplements that cannot be patented.

In contrast to drugs, however, the right foods and combination of nutrients can be preventative – working naturally with and enhancing the body’s own biochemistry.

3. But isn’t there research to show that supplements don’t work?

Some, yes – but the overall results are mixed.

For example the Physicians’ Health Study II investigated the effects of daily multi-vitamin use in over 14,000 middle-aged, male doctors. It found no reduction in heart attacks or strokes, and no reduction in mortality.

However, a 2015 study on 8,678 women, published in The Journal of Nutrition, found that those women who took a multivitamin for at least three years had a 35% lower risk of dying from heart disease.

Some studies on the use of multi-vitamins have found no effect on cancer risk. On the other hand a large meta-survey, combining the results from 5 randomized, controlled trials and involving 47,289 participants, found a 31% lower risk of cancer in men, but no effect in women.

Can multivitamins improve brain function? Again the results are mixed. A placebo-controlled, double-blind study (the gold standard) on elderly women did show improvements in memory – but not on general reasoning tasks.

The composition of the supplement is key

The confusion is not surprising. We would not expect a simple, RDA-based, multivitamin and mineral pill to make a lot of difference – especially to a person already eating healthily. The levels are not optimum nor is the range of nutrients enough.

No less an authority than the Journal of the American Medical Association agrees. A scientific review of 150 clinical trials published by them concludes that:

“… the normal diet is sufficient to prevent overt vitamin deficiency diseases such as scurvy, pellagra, and beriberi.

“But recent evidence has shown that suboptimal levels of vitamins, even those well above those causing deficiency syndromes, are risk factors for chronic diseases such as cardiovascular disease, cancer, and osteoporosis.

“A large proportion of the general population is apparently at increased risk for this reason.”

[Our emphasis on deficiency and suboptimal.]

So let’s now change the initial question.

I eat healthily – so what supplement
would make a difference?

On the basis of this article, the answer is a supplement containing nutrients that are shown to help prevent, reduce or slow:

1. Damage to DNA
2. The inflammation that develops in body tissues
3. The gradual decline in immune function
4. The mistakes that are made in the new cells you make each day
5. The ‘glycation’ or ‘sugar coating’ of cells.

That supplement should also contain nutrients that can help ‘turn on’ protective genes, and ‘turn off’ damaging genes like oncogenes.

The following list of protective nutrients is compiled from literally thousands of peer reviewed scientific studies. You’ll see that some nutrients have more than one role in a multiple health defence strategy. They should all be in included in a genuinely effective supplement.


Humans have extensive DNA repair mechanisms, but these begin to weaken with age, causing DNA damage to accumulate. This not only accelerates ageing, but increases the risk of cancers and, for example, the irreversible eye disease macular degeneration.

I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and Minerals
Tomatoes are high in lycopene

The carotenoids lycopene, lutein and zeaxanthin have been shown to assist DNA repair and reduce damage – as have the minerals selenium and zinc.

Grapeseed extract – rich in plant polyphenols called anthocyanins – has also been shown to block breast cancer cell DNA damage.

Oxidation or excess free radical action is also a factor in DNA damage and vitamin C, vitamin E and CoQ10 are all powerful antioxidants at the right level.


‘Chronic, sub-clinical inflammation is now known to be a major cause of the degenerative killer diseases.

This type of inflammation builds up in tissues over time, but you can’t see or feel it – which is why Time Magazine calls it ‘the silent killer’.

New Scientist recently confirmed that …

“… inflammation is involved in muscle wasting and glaucoma, Alzheimer’s and Parkinson’s, osteoporosis and arthritis, heart failure and high blood pressure, cancers, and lung, liver and kidney and skin disorders.”

I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and Minerals
Curcuminoids are found in the curry spice turmeric

The incidence of inflammation increases with age and is a risk factor for most people after the age of about 50. The risks rise even further if you live in a city and are exposed to air pollution.

Some of the most potent anti-inflammatory supplement nutrients are Omega 3 fish oil, curcumin, the plant polyphenols in green tea and anthocyanins which are the nutrients that contribute the rich red, blue and purple colours to the leaves, roots and fruits of plants.

An anti-inflammatory diet includes oily fish, berry fruits, olive oil, tomatoes, leafy green vegetables and nuts. It also calls for less refined carbs, processed meats and fried foods.


Your immune system defends you against pathogen invaders like viruses and dangerous bacteria and against internal ‘rogue’ cells like cancer.

I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and MineralsFoods that support the immune system include mushrooms (especially shiitake and maitake), dark berry fruits, leafy green vegetables, green tea and garlic.

Supplement nutrients that support the immune system include vitamin A, beta carotene, vitamin D, vitamin E, curcumin, green tea extract, selenium, zinc and lycopene.


Every one of the billions of cells that you make every day needs a source of high quality fats in the diet to form a healthy, flexible outer membrane. Omega 3 from oily fish is an ideal source.

I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and MineralsIn addition, each cell must be able to sense its boundaries. They do that by what is called ‘cell signalling’. When they cannot signal their boundaries, the result can be uncontrolled cell growth – cancer.

Researchers have found that vitamin D, the carotenoid lycopene, the xanthophyll carotenoid lutein and the B vitamin choline are important to ensure normal cell signalling and, by extension, cut the risk of cancer.

The American National Institutes of Health website Pub Med confirms that

“carotenoids can be useful in the prevention of cancer and other degenerative diseases”

Healthy cells also need CoQ10.

Inside almost every cell in your body are mitochondria – the tiny ‘power plants’ that help break down food and create energy.

A significant factor in ageing and disease is a progressive loss of mitochondrial function – which can result in lower energy levels, heart disease, diabetes and neurological problems.

Mitochondrial cells include DNA and because of the high energy levels created within them – especially in heart cells – mitochondrial DNA is very vulnerable to oxidation or free radical damage.

Coenzyme Q10 is a vital nutrient within the mitochondria and an amazing 95% of all cellular energy production depends on it.

Unfortunately levels of CoQ10 peak at about 20 years of age and decline continuously thereafter. However studies show that CoQ10 supplementation can boost mitochondrial function and total energy output in heart muscle, as well as protect tissue from DNA damage.

CoQ10 is also a powerful anti-oxidant and one of the few nutrients that can enter mitochondrial cells. There it counteracts the damage caused by free radicals. The more CoQ10 that is available to the mitochondria, the less free radical damage and potentially the slower you age.

CoQ10 is not the only important heart nutrient. Studies show that a nutrient called betaine, with other B vitamins and folic acid, can lower a dangerous blood protein called homocysteine. High levels of homocysteine lead to an elevated risk of heart attacks.

Food sources of CoQ10 are mainly organ meats like kidney and liver, plus beef, sardines and mackerel. Betaine is found in quinoa, wheat bran and beets (which is where its name comes from).


I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and Minerals
Wheat bran is high in B vitamins

Glycation is when a sugar molecule binds to a protein. This ‘sugar coating’ leads to tissues becoming ‘cross linked’, rigid and less pliable.  It is strongly linked to accelerated ageing, wrinkles and more seriously, a worsening of degenerative diseases like diabetes, cataracts, atherosclerosis, kidney disease and Alzheimer’s.

Glycation is mainly a function of excess sugar and carbohydrates in the diet, together with high temperature cooking like frying and roasting. Hence it’s more about what you do NOT eat – and exercising enough to burn up the sugars in your bloodstream.

However, studies show that the B vitamins B1, B6 and folic acid may help reverse the damage caused by glycation.


I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and Minerals
Tofu is made from soybeans

Certain nutrients can upregulate or turn on ‘good’ genes – like tumour suppressor genes. And others can down-regulate or turn off ‘bad’ genes – such as oncogenes which have the potential to cause tumours.

It’s called ‘gene expression’, part of a new science called epigenetics.

Scientists in this emerging field have identified a number of nutrients that can trigger positive gene expression – they include betaine, folic acid, choline, vitamin B12, vitamin D, lycopene, selenium, lutein, green tea and genistein which is derived from soy.

The ideal COMBINATION of nutrients in a supplement

The above is a summary of the range of nutrients that can make a genuine difference to health. But that’s only one aspect.

They now need to be brought together in a synergistic combination at optimum levels.

The optimum research-based levels for the main nutrients are listed here.

Adequate versus optimum – the vitamin C example

But let’s look at how the ‘adequate’ versus ‘optimum’ argument plays out for one common but vital vitamin – vitamin C.

I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and Minerals
Everyone knows citrus fruits are high in vitamin C

The EU RDA/RNI for vitamin C is 80 mg. Now here is what vitamin C does:

  • It is needed for over 300 metabolic reactions including production of collagen
  • It has natural anti-viral and anti-bacterial actions
  • It is important for wound healing
  • It is a powerful anti-oxidant which regenerates other anti-oxidants like vitamin E
  • It helps protects DNA from damage

Research shows that vitamin C can also achieve the following – BUT only at levels that average 500 mg a day – over 6 times the RDA:

  • It improves blood flow in people with diabetes
  • It reduces levels of the damaging cholesterol LDL
  • It significantly lowers the risk of heart attacks and stroke
  • It reduces the incidents of cataracts – in people who supplemented for over 10 years the reduction was 83%!
  • It can reduce the risk of pneumonia
  • It can reduce the risk of catching a cold by 30%
  • It reduces the risk of gout
  • It stimulates bone building cells (called osteoblasts), enhances vitamin D activity and boosts calcium absorption – so it is important in preventing osteoporosis
  • It helps reduce the risk and severity of osteoarthritis
  • It is now thought to help protect against stomach cancer – possibly by inhibiting the growth of H. pylori bacteria
  • It improves sperm quality, numbers and motility
  • Elderly people with the highest levels of vitamin C intake have a lower risk of cognitive impairment

The results of optimising vitamin C levels give the lie to critics that dismiss supplements as ‘only creating expensive urine’.

In fact, the body absorbs ALL the vitamin C it needs – and a single 500 mg dose is almost 100% absorbed through an active transport process.

It is true that a decreasing percentage is absorbed at much higher doses and that the upper safe limit for long term use has been set at 1,000 mg a day.

A comprehensive supplement at optimum levels

We’ve seen that there are multiple ways in which health can deteriorate as we get older. To defend against these threats you need multiple nutrients – nutrients that research shows have the power to counteract these threats. This combination must be at optimum levels.

However conscientious you are, it is difficult to eat to achieve a continuous DAILY intake of nutrients as diverse as lutein, lycopene, Omega 3, curcumin, beta carotene, CoQ10,  polyphenols like anthocyanins, green tea, and the isoflavone genistein.

Let alone to reach the optimum rather than just RDA levels of all the essential vitamins and minerals.

I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and Minerals

That’s why the multiple ingredient supplement called NutriShield Premium was originally developed by Dr Paul Clayton. It includes all the nutrients we have identified, in the most bio-available forms, combined in a comprehensive, highly concentrated, zero calorie health supplement.

Of course this high level of nutrition cannot be put into just one vitamin pill. NutriShield Premium consists of 6 daily caplets packed into a tear open sachet – which saves not only buying multiple bottles of supplements, but ensures the nutrients are always optimally balanced.

The full list and levels are given here.

Naturally NutriShield Premium costs more than a simple vitamin pill but – like eating well – the investment is comparatively minor compared to the long term gains.


If you enjoyed this article, please share it with family and friends. You can follow us on Facebook or Twitter for daily headline health tweets.


I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and MineralsRegister now for a free monthly e-newsletter on the latest in nutrition and health research.

Dr Paul Clayton designed NutriShield as a comprehensive healthI eat healthily - why do I need a supplement? NutriShield Multi Vitamins and Minerals supplement with OPTIMUM levels of essential nutrients. See more detail elsewhere on this site or click on the button.

I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and MineralsDr Paul Clayton’s best-selling book Health Defence is available from booksellers.

Read it here online or see the website www.healthdefence.com for excerpts and links to buy direct from the publisher.

See online here for delicious recipes from the Health Defence Cookbook incorporating healthy foods featuring in a Mediterranean Diet. I eat healthily - why do I need a supplement? NutriShield Multi Vitamins and Minerals




The importance of the ratio of omega-6/omega-3 essential fatty acids. Simopoulos AP, Biomed Pharmacother. 2002 Oct;56(8):365-79.

Lymphocyte Lycopene Concentration and DNA Protection from Oxidative Damage Is Increased in Women after a Short Period of Tomato Consumption. Marisa Porrini and Patrizia Riso; Curr Cancer Drug Targets. 2007 Aug;7(5):425-31.

Nutrition and DNA repair–potential molecular mechanisms of action. Mathers JC, Coxhead JM, Tyson J.

Enzymatic formation of apo-carotenoids from the xanthophyll carotenoids lutein, zeaxanthin and β-cryptoxanthin by ferret carotene-9′,10′-monooxygenase. Mein JR, Dolnikowski GG, Ernst H, Russell RM, Wang XD. Arch Biochem Biophys. 2011 Feb 1;506(1):109-21. Epub 2010 Nov 21.

The carotenoid beta-cryptoxanthin stimulates the repair of DNA oxidation damage in addition to acting as an antioxidant in human cells. Lorenzo Y, et al 2009 Feb;30(2):308-14.

Dietary carotenoid lutein protects against DNA damage and alterations of the redox status induced by cisplatin in human derived HepG2 cells. Serpeloni JM et al;  Toxicol In Vitro. Mar 2012;26(2):288-94.

A role for supplements in optimizing health: the metabolic tune-up. Review. Ames BN; Arch Biochem Biophys. 423(1): 227–34.2004.

Advanced glycation end products key players in skin aging? Paraskevi Gkogkolou and Markus Böhm; Dermatoendocrinol. 2012 Jul 1; 4(3): 259–270. doi:  10.4161/derm.22028

Long-latency deficiency disease: insights from calcium and vitamin D. Robert P Heaney; 2003 American Society for Clinical Nutrition

Multivitamin-mineral use is associated with reduced risk of cardiovascular disease mortality among women in the United States. Bailey RL et al; J Nutr. 2015 Mar;145(3):572-8. doi: 10.3945/jn.114.204743.2015 Jan 7.

The efficacy and safety of multivitamin and mineral supplement use to prevent cancer and chronic disease in adults: a systematic review for a National Institutes of Health state-of-the-science conference. Huang HY et al; Ann Intern Med. 2006 Sep 5;145(5):372-85. Epub 2006 Jul 31.

Effects of a multivitamin, mineral and herbal supplement on cognition and blood biomarkers in older men: a randomised, placebo-controlled trial. Harris E et al; Hum Psychopharmacol. 2012 Jul;27(4):370-7. doi: 10.1002/hup.2236. Epub 2012 Jun 18.

Vitamins for Chronic Disease Prevention in Adults: Clinical Applications. Robert H Fletcher, MD, MSc; Kathleen M. Fairfield, MD, DrPH; JAMA. 2002