Most body cells don’t live very long. Not when you consider that the average human in the UK lives for about 80 years. The most longevity you can expect from any of your cells is, of course, a lifetime, and some neurons do live up to this expectation, but most have a transient existence compared to ‘us’.

Some of the most rapid cell turnover comes from the lining of our mouths and stomach; our blood; and from our skin, hair and nails. Our cells are always dying off without us ever really noticing – your body carries on helpfully replacing those that have come to the end of their road. You eat that delicious lunch, your body digests it, disassembles the components, chucks out the waste and recycles the useful bits to power our functions and make new cells. By trying not to align myself with a certain TV – and I use this in the flimsiest sense of the word – “nutritionist”, I have gone a rather roundabout way to say: you actually are what you eat.

Our skin, hair and nails are made of cells consisting of things such as proteins, fats, carbohydrates and water. Different types of cells are made in different ways and require different nutrients for the process to work. Hair and nails are largely made of a protein called keratin, which requires vitamin A for its formation. Skin contains a protein called collagen that provides strength to the structure of cells. The body cannot produce collagen unless there is sufficient vitamin C on hand, and if you have heard of scurvy, then you’ll know what the effects of long-term vitamin C depletion are. Fortunately, scurvy is not common in the UK.

Let’s have a look at a few key players:

Vitamin C:
Many face creams, shampoos, hair treatments and manicures promise you that putting a bit of this and that on your skin will make your skin/hair/nails this that and the other. It is worth noting that the dermis of your skin consists of several layers which the chosen topical ointment will need to battle through before it reaches anything that is in the business of producing new skin cells. So, although vitamin C is in a lot of cosmetics and marketed as “collagen-boosting” it is unlikely to be as effective as getting enough through your diet. It’s also worth noting that, unlike your skin (which is an organ and one of only two that can self-repair – the other is the liver), by the time your hair and nails become visible they are pretty much past it and their constituent cells are certainly beyond improvement. That is why shampoo manufacturers only say that their products will give you “healthy-looking” hair and not “healthy” hair, because dead things can’t ever be considered healthy and advertising regulations (thankfully) prohibit misleading claims.

Vitamin C is also an antioxidant, meaning that it helps neutralise free radicals. Free radicals are the by-products of various processes in the body and they are known to attack DNA and cell membranes. Some people believe that getting enough antioxidants can offer a bit of protection against the ageing process and preserve youthful, wrinkle-free skin, but others disagree completely so the jury is still out on that one.

Vitamin A:
Vitamin A is important in the growth of epithelial cells (a type of cell found in skin, among many other places) and for the production of keratin. One of the symptoms of vitamin A deficiency is rough, bumpy skin around the hair follicles. A word of caution though: too much vitamin A is toxic and large intakes while pregnant can cause miscarriage.

Vitamin B complex:
Riboflavin (B2) and niacin (B3) have both been classified by the European Food Safety Authority as being physiologically effective in the maintenance of normal skin as has biotin on the maintenance of hair and nails.

Folate:
Folate (or folic acid as it is know in its synthetic state) is central to the process of cell division. Actively dividing cells need plenty of this stuff to divide properly – your skin cells are dividing all the time.

Zinc
Zinc is a mineral that is sometimes known for its purported aphrodisiac qualities but less often for its role, alongside vitamin C, in collagen production.

So can what we eat really affect the way we look? Well yes it can, but let’s not get carried away. The vitamins and minerals we’ve discussed here are abundant in the diets of the average person in the UK and deficiencies are rarely found here.

Should you take supplements? You probably don’t need to take supplements of these vitamins, with the exception perhaps of folic acid if you are female and of childbearing age as adequate quantities protect against neural tube defects such as spina bifida. Eating a balanced diet is usually better for the average citizen. Take a look at the list of foods below to see the best sources of these micronutrients. You should consult your doctor before taking any supplements, particularly if you are taking any medication or if you are – or are trying to become – pregnant.

Food sources
Vitamin A: Liver, whole milk, cheese, butter, fish, fortified margarine, carrots, watermelon, tomatoes
Vitamin B complex: Whole grains, fortified cereals, meat (B3) liver (biotin), egg yolk (biotin). Biotin is also produced by the body.
Vitamin C: Asparagus, papaya, citrus fruit and their juices, cauliflower, broccoli, green peppers
Folate: Mushrooms, green leafy vegetables, beans, legumes, oranges, liver
Zinc: Red meat, oysters, dairy products, whole grains, leafy vegetables

References
Advanced Nutrition and Human Metabolism 5th Ed. Wadsworth
National Diet and Nutrition Survey
European Food Safety Authority
UK Office for National Statistics