Can vitamin pills protect you from cancer?

Winter is just around the corner, and with the fresh threat of a second wave of Covid-19, you are probably thinking of giving your immunity a boost by buying some vitamin pills.

If so, you’re hardly alone — up to 70 per cent of us admit to taking supplements regularly or intermittently.

Each year in the UK we spend £442 million on mineral and vitamin supplements — and sales of these and other nutritional products have jumped by 17.3 per cent since last year, according to the Health Food Manufacturers’ Association.

There is a lot of confusion about what supplements actually are — people tend to refer to all supplements as vitamins and minerals — but that’s only one category of this expanding nutritional market.

Others include extracted phytochemicals, proteins, probiotic bacteria and concentrated whole foods, which all have different roles to play in our health.

But given the vast array of tablets out there, which should we take?

In our series so far, I’ve been explaining why I believe our diet and lifestyle can be more important than the genes we inherit. 

This conviction is based on a lifetime’s work as an NHS consultant oncologist, as well as my own years in research clinics studying how different food and habits can help cancer patients — and everyone else.

It’s also the subject of my new book, How To Live, in which you’ll find more science-based advice on how to cut your cancer risk and live a healthier life.

So no one is keener than I am to investigate precisely how different elements in our food might help our health and our battle against cancer in particular.

It’s generally well-known that severe deficiencies in vitamins, minerals and healthy fats can damage your immune system, leading to a range of diseases including heart disease and type 2 diabetes as well as cancer.

For example, the well-known Epic (European Prospective Investigation into Cancer) study reported that people deficient in vitamin A, C and E had an increased risk of breast, ovary and other cancers.

Despite the availability of food, many of our diets are not as nutritious as they could be.

For instance, did you know as a nation our biggest source of vitamin C is actually potatoes, not because they are particularly high in the vitamin but simply because we eat so many of them (and generally speaking relatively little fruit, which is packed with vitamin C).

Alarmingly, as countries get richer, the diversity of the typical diet shrinks. Today, 75 per cent of the world’s food supply comes from only 12 plants and five animal species.

The solution eagerly suggested by the supplement industry would be to take mineral and vitamin pills.

But is it that simple? As someone who’s studied the research extensively, I have to say that it’s a mixed picture.

Scientists mostly agree that supplements and tablets are not needed at all if you’re eating a balanced nutritious diet — and our bodies really are efficient at extracting beneficial minerals and vitamins out of our food.

That said, we do live in the real world and I accept that not everyone is as motivated as I am to eat a wide range of different vegetables, fruit and herbs every day (though I hope that this series will encourage you to make some changes to this!)

And although they may not do any good (and aren’t always cheap) most supplements are safe.

However, there is evidence that certain types of supplement — particularly those high in vitamins A and E — can actually do harm.

Vitamins A and E are both powerful antioxidants that act directly to mop up free radicals, which as we’ve seen can go on to cause cell mutations and cancer.

While it’s almost impossible to consume too much in your diet — this isn’t true if you isolate them into concentrated form in a tablet.

The problem is that these antioxidants don’t have an off-switch — so taking too many of them doesn’t just mop up excess free radicals, but goes on to destroy more, and in doing so upsets the ‘oxidative balance’ in your cells (which is actually needed for healthy functioning). In fact, large studies show that too much vitamin A and E can actually increase your cancer risk.

This is why the World Cancer Research Fund and Memorial Sloan Kettering Hospital have issued statements that taking long-term mineral or vitamin supplements, without a recognised need, is not required and could do more harm than good.

But I’ll look at this in more detail later.

Evidence shows you should also be wary of fish oil supplements. Although their high content of omega 3 and omega 6 fatty acids is beneficial (as they play a key role in regulating our immune systems and cannot be manufactured by our bodies), some studies are now suggesting that they might actually increase men’s risk of prostate cancer, particularly if they take them regularly over periods of time.

It’s thought that may be partly related to an excess of vitamin E, but more research is needed.

But based on my experience and all the research I’ve conducted, in my view it really is best to eat the whole food — or a supplement containing a wholefood concentrate — rather than trying to drill down and isolate individual minerals, elements and micro-nutrients.

A good illustration of this is the well-loved tomato, staple of sauces, salads and dishes all over the world and shown to have many healthy properties.

Population studies show that people who eat more tomatoes have a lower cancer risk, which has been attributed largely to the phytochemical lycopene, as I explained on Saturday.

Yet lab studies didn’t back this up. Research looking at the benefits of lycopene didn’t show anti-cancer benefits (though those involving extract of whole dried tomato did). 

And a prestigious Cochrane review in 2011 had insufficient evidence to demonstrate a benefit between lycopene supplements and prostate cancer incidence.

A great deal of focus has traditionally been placed on vitamins and minerals, but as I’ve previously explained, the vital role of phytochemicals — naturally occurring compounds in fruit and vegetables, herbs and spices that are massively beneficial to our health — tends to have been overlooked.

These are contained in food supplements made from concentrated whole foods and in my view have a useful role to play in overcoming dietary deficiencies — particularly during times of oxidative stress or inflammation, which can lead to cancer.

They are also useful to take when you are recovering from a virus — and trials are currently under way examining how phytochemicals may help in the fight against Covid-19, for instance — or undergoing chemotherapy or following surgery.

An increasing body of new research is beginning to demonstrate these considerable benefits of whole food supplements — including the Pomi-t trial I was involved in (see box on the right), which demonstrated that a supplement containing a combination of pomegranate, turmeric, broccoli and green tea can slow the progression of prostate cancer.

It’s certainly an exciting and developing area of research — with new discoveries continually being made about how this can improve our immune systems in general and help us combat the risk of cancer, too.

The ABC of vitamins and supplements

They’re vital to our health and wellbeing and you may feel you already know a bit about vitamins. But do you really understand how they can help you fight cancer? Here’s my ABC of what you need to know:

Vitamin A

What: Vitamin A is a fat-soluble pigment found in fish and dairy food.

Vitamin A can also be made by the body using the carotenoid group of polyphenols (found in orange fruit and vegetables from carrots to pumpkins and apricots).

Why: Important for forming healthy cells in our skin, the cornea of the eye, and the membranes of your mouth.

Vitamin A is a powerful antioxidant which acts directly on free radicals.

Although diets high in vitamin A are healthy and linked to a lower risk of many diseases, the same cannot be said of supplements, because they offer concentrated doses of vitamin A. 

This, as I explained earlier on, can upset the ‘oxidative’ balance by destroying too many free radicals (and as we’ve seen your body needs some in order to function properly).

Two large studies giving extra vitamin A to smokers had to be stopped because of an increased lung cancer rate. Another large human dietary prevention study found that men who started the trial with low blood levels of vitamin A had lower levels of prostate cancer after years of taking a vitamin A supplement.

However, men who had high initial levels of vitamin A ended up with a higher risk of prostate cancer.

The clear take-home message here is this: correcting a natural or acquired deficit is beneficial but, too much of a good thing, in this case a single antioxidant, can be harmful.

Found in: Oily fish, cod liver oil, other fish oils; beef, pork, lamb, chicken liver and kidney; eggs, milk, cream, yoghurt and cheese.

Vitamin B

What: There are several subtypes of these water-soluble vitamins: B1 (thiamine), B2 (riboflavin), vitamin B6 (pyridoxine), B9 (folic acid) and B12 (cobalamin).

Why: This group helps the body turn food into energy and is also key for brain development and producing red blood cells.

B vitamins have a complex relationship with cancer risk. Studies show women with a diet high in B vitamins have a lower risk of breast cancer — and also that people deficient in B vitamins had an increased risk of cancer, especially of the bowel.

A combined analysis of two studies from Norway investigating whether giving people vitamin B supplements after a heart attack would aid recovery actually reported a slightly higher incidence of subsequent cancers.

Found in: Grains such as wheat, barley, and oats (B1 and B2), leafy green vegetables (B6 and B9), plus beetroot, chickpeas, salmon, tuna and citrus fruits, meat and some legumes (B12).

Vitamin C

What: Vitamin C is an essential water-soluble nutrient which humans need to eat on a daily basis. The body cannot manufacture its own supplies and it only lasts for a short period in the bloodstream.

Why: It plays an important role in the functioning of several enzymes, healing wounds, and repairing and maintaining bones and teeth. It also helps the body absorb iron from non-meat sources such as vegetables and nuts.

It’s often described as an antioxidant, but this is not actually correct, as it cannot act directly to neutralise free radicals in the same way that vitamins E and vitamin A can — even at high doses.

But it is involved in a mechanism which enables DNA to ‘sense’ the oxidative damage being done by free radicals, viral and bacterial infection — so, in this respect, it is a vital part of DNA repair to prevent potential cancer-forming mutations.

There’s evidence vitamin C may also have cancer- protective properties by limiting the formation of carcinogens — these include some of the toxins produced when your body digests meat for instance.

Research also shows that higher consumption of fruits and vegetables is associated with lower risk of most types of chronic disease, including cancer. This may be in part due to their high vitamin C content.

Several studies show that chronic deficiency can increase the risk of cancer.

A recent review reported that women who either took vitamin C supplements or increased their dietary intake of vitamin C after being diagnosed with breast cancer significantly reduced their risk of dying from it.

However, research shows that while being deficient in vitamin C increased the risk of cancer — eating more than the recommended amount had no effect.

And although there is currently a trend for intravenous vitamin C infusions as an alternative therapy or health kick, there are no robust trials or credible data to back up its use — other than perhaps for someone with a genuine vitamin C deficiency.

Unlike vitamins A and E, however, there’s no data to show that taking high amounts of vitamin C can cause cancer.

If considering a supplement, I recommend you take no more than 100mg a day.

Found in: Citrus fruits, cherries, guavas, yellow peppers, blackcurrants and blackberries are particularly rich in vitamin C.

Vitamin D

What: Vitamin D plays an important role in regulating the amount of calcium and phosphate in the body — nutrients needed to keep bones, teeth and muscles healthy.

Why: Research has shown that vitamin D can help to protect you against the risk of kidney, bowel and prostate cancer.

Numerous studies show it also has direct abilities to slow cancer growth and delay its spread.

Survivors of bowel cancer with regular exposure to sunlight and higher vitamin D levels were found to have a lower risk of relapsing.

But most fascinating of all, as I explained in Saturday’s paper, is a study that focused on people who’d been treated for melanoma skin cancer. As this disease increases with sunburn, these patients had been told to avoid direct sunlight after their diagnosis.

However, those who ignored the advice and continued to have regular sun exposure were subsequently found to actually have a lower risk of the melanoma spreading due to a deficiency of vitamin D.

And there’s evidence that being overweight (itself a cancer risk) can lead to vitamin D deficiency — an extra reason why losing a spare tyre can cut your cancer risk.

The authors of the Genetic Investigation Of Anthropometric Traits (Giant) study, which followed 120,000 people, concluded that because vitamin D was stored in fatty tissue, obese people therefore had less circulating in their blood and available to combat arthritis, osteoporosis, infertility, and dementia — as well as cancer.

Found in: Your body needs exposure to sunlight to create about 80 per cent of the vitamin D it needs — with the result that many people are vitamin D deficient during the winter months so could benefit from a supplement. It is also found in a small number of foods including oily fish, red meat, liver, eggs.

Vitamin E

What: A fat-soluble direct antioxidant with anti-inflammatory properties that’s found in a wide range of seeds, nuts, vegetables, healthy oils and oily fish.

Why: Vital for a healthy immune system, smooth muscle growth and neurological functions. Like vitamin A, it can act directly to neutralise cancer-causing free radicals, which makes it a powerful ally for your immune system. However, while it’s important to correct deficiencies, in reality severe vitamin E deficiency is rare.

The large Select study (Selenium and Vitamin E Cancer Prevention Trial) which gave vitamin E to a group of men over several years actually showed an increased incidence of prostate cancer.

But you’re not likely to consume excessive levels of vitamin E from your diet alone — and I would encourage you to ensure your diet is rich in this vitamin.

Found in: Pistachios, almonds, hazelnuts, spinach, Swiss chard, fresh fruit, cruciferous vegetables, whole wheat, sunflower and pumpkin seeds, extra-virgin olive oil, sunflower oil, rapeseed oil, avocado, butternut squash, sweet potato, trout, mackerel, peas, soy and broad beans.

Vitamin K

What: Vitamin K is a collective term for a number of essential fat-soluble nutrients, the most prominent subtypes being vitamins K1 and K2.

Why: All K vitamins play a significant role in regulating blood flow, helping to form clots following a cut or surgery and prevent them when they are not needed. Vitamin K2 is essential for bone formation and health, ensuring that calcium is absorbed easily into the bone mass.

Fascinatingly, it has the opposite effect in the walls of your arteries — where it prevents the build-up of calcium that can harden them, leading to heart attacks, strokes and poor blood supply in the legs.

Vitamin K2 is found in fermented products — including blue-veined cheeses such as Stilton or Roquefort, so eating these can help to strengthen your good gut bacteria (which in turn helps your body to fight cancer) as well as building healthy bones.

Laboratory tests have consistently demonstrated direct anti-cancer effects of vitamin K.

Found in: Spinach, kale, beetroot, cabbage, green beans, chicken legs and wings, eggs, berries, avocados, grapes, pomegranates, bread, cereals, olive and sesame oils (K1). 

Fermented soy, fermented hard cheeses, Stilton, Gouda, Edam, egg yolk, soy beans, sauerkraut, tempura, kombucha, kimchi, natural live yoghurts and meat from grass-fed animals.

How to protect you and your family from toxins

Living a life totally free from toxins and carcinogens is just not possible. It’s also unnecessary, as the body’s antioxidant defences are able to cope with a certain amount of them.

It’s only when these potentially cancer-causing substances are absorbed, inhaled or consumed in excess that our defences get overwhelmed and health problems start.

The harm these environmental toxins do to our DNA depends on the amount we take in over time — and whether we’re also consuming chemicals from other sources that increase your overall toxic load. 

The problem is that what constitutes excess varies from one individual to another, as many factors play a part — including genetic susceptibility and lifestyle habits.

The good news is that it’s also possible to off-set the impact of carcinogens we encounter, for example by increasing the amount of phytochemicals we eat in our diet and by doing exercise.

Here, I’ll look at everyday hazards and what the latest research shows about the threat they pose to our health and our chances of developing cancer. Individually they might not seem particularly dangerous — but if you combine them or add them to a sedentary, high-sugar, super-fast lifestyle, you may find it’s another story.

Vehicle emissions and plastic contaminants

Some environmental pollutants are damaging because they have a chemical structure similar to the hormone oestrogen — and this stimulates certain tissues to grow rapidly, often in an uncontrolled way.

These are known as xenoestrogens and they’re found in fuels, car emissions, plastic bottles and containers. Other xenoestrogenic chemicals include dioxins, which are released in some industrial processes, and bisphenol A (BPA) a chemical used for making tough, polycarbonate plastics.

It’s difficult to avoid these chemicals in today’s environment and it’s a sad fact that the quantity of plastics found in the sea, rivers and lakes is increasing exponentially.

On top of this, chemicals can seep from packaging materials into the foods we eat and drink. When thrown onto rubbish dumps or into lakes and oceans, they also filter into the water supplies and soil, contaminating the plants and animals we eat.

Endocrinologists and reproductive biologists have suggested that long-term exposure to xenoestrogens is responsible for the rise in endometriosis and fibroids in women and decreasing sperm levels in men.

In terms of cancer, a publication linked an increased rate of testicular cancer in men with pollutant oestrogenic chemicals in their mother’s milk and later in their water supply.

Likewise, an analysis of chemical plant workers in Hamburg, Germany, discovered a two-fold increase in breast cancer among the female workers who had been exposed to dioxin contamination.There are multiple reasons why these chemicals cause cancer. Some are mutagenic so directly damage DNA; others increase inflammation, which drives cancer cells and weakens immunity. Others can cause susceptible cells to grow faster.

Polluted air from outdoors can get trapped inside our homes, adding to the contaminants being emitted by cleaning products, paint and furnishings.

My own conclusion is that we could reduce our exposure to these risks significantly by going back to the way we used to live 50 years ago. Walk and exercise away from cars. Buy food, as we did before the plastic revolution, from local producers and choose foods that are in season (rather than sprayed with preservatives and flown across the world). 

Should you worry about mobiles? 

Mobile phones emit heat and radio frequency energy from their antennas and batteries. This can be absorbed by the skin, the ear, the parotid salivary gland, the lining of the brain and the brain itself. Other tissues can be affected if the device is stored next to the skin.

Given that 95 per cent of the UK population now has a mobile, a vast number of people would be affected if the energy produced by mobiles affected your risk of cancer even slightly.

This is why several public health organisations have conducted detailed investigations to see if the incidence of cancer has increased in the tissues nearest to the mobile device.

However, the Surveillance, Epidemiology and End Results (Seer) programme found no overall increase in the incidence of brain cancer between 1992 and 2006, despite the increase in mobile phone use in the same period.

Despite the lack of evidence of direct harm caused by mobile phones, the International Agency for Research on Cancer (IARC) and World Health Organisation (WHO) still classify them as ‘possibly carcinogenic to humans’.

The American Cancer Society also suggests that there could be some cancer risk associated with radio frequency energy. However, further evidence is needed.

It advises people to limit their radio frequency energy exposure by reducing mobile phone use and to avoid storing your phone in your change pocket (next to your testes if you’re a man) or breast pocket (if you’re a woman). 

Don’t fret about masts 

There’s also been speculation about the links between cancer and living near a phone mast.

However, researchers at Oxford University studied data from all 81,781 mobile phone towers in the UK and found no correlation between the masts and cancer.

Extracted by Judith Keeling from How To Live by Professor Robert Thomas, published by Short Books at £14.99.

© 2020 Professor Robert Thomas. Order a copy for £12.74 at mailshop.co.uk/books or call 020 3308 9193. Free UK delivery on orders over £15. 

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