Imagine a consultation with your doctor or nutritionist in the not too distant future. Instead of making an educated guess about which medicine or supplements you need, and changing the dose according to how you respond, your doctor will first check a sample of your DNA. This will be collected painlessly from a simple cheek swab – or even a fingerprint – rather than anything as antiquated as a drop of blood. Once the technology is advanced, you will just hand over your personal swipe-card on which your individual genome is digitally recorded.
Within seconds, your genes will be analysed, and your doctor or nutritionist will know which exactly which drugs and supplements will suit your individual genetic make-up. These tests will predict how well you will respond to different medicines or herbal treatments, what doses you need, and whether or not you would develop unwanted side effects. Rather than the hit-and-miss approach of today, your doctor and nutritionist will individually tailor your prescriptions for you. Although this may sound far-fetched, much of the technology is already in place, and this rapidly evolving new branch of science even has a name – pharmacogenomics.
The information encoded within your genes
Your genetic information is contained within molecules called DNA (deoxyribonucleic acid), whose structure resembles a long, spiral ladder. The rungs of the ladder are made up of around 3 billion pairs of sub-units known as nucleotides. Surprisingly, there are only four different nucleotides, referred to as A, T, C and G, but the order in which these sub-units occur along the DNA helix acts as the code needed to make particular proteins. The code essentially tells each cell the order in which to place amino acids when making different protein chains. The stretch of DNA that provides all the coding needed to make a single protein is known as a gene.
We each have around 20,000 genes within our DNA, which together make up our individual genome. Each gene exists in many different forms within the population, due to the exact order of its A, T, C and G sub-units. Although we each inherit the same number and type of genes, the subtle differences within them make each of us unique from the other 6.5 billion people on this planet.
Since your genetic instructions differ slightly from those of other people, the proteins you make from that genetic code also differ slightly. Some of these proteins (which include enzymes) determine how your body handles certain drugs – the way they are absorbed and distributed throughout your body, how they interact with your cells, and how they are broken down and eliminated from your body. That’s why some people do well with certain drugs while others develop side effects. It all comes down to your genes.
It’s all in your snips
The ability to link genes with drug reactions took a leap forward in the late 1990s with the discovery of SNPs (single nucleotide polymorphisms – pronounced ‘snips’). These one-letter variations in the normal genetic code occur when a single nucleotide in the DNA sequence has changed. For example, a section of DNA within a particular gene might normally contain the sequence: GATTACA, but someone might inherit a copy of that gene which reads GAATACA instead – the first ‘T’ nucleotide in the sequence has been replaced by an ‘A’. These single variations, or SNPs, are common and at least 5 million have been identified.
Most SNPs are benign, and have no significant effect on the protein coded for by that gene. They just act as a useful marker for scientists to know which particular versions of a gene you have inherited. A few SNPs can cause crucial changes, however, so that, for example, an enzyme involved in drug metabolism no longer works properly. This might happen because a different amino acid is inserted when an enzyme is made, so it folds into a different three-dimensional shape.
Because of the individual SNPs we have inherited, many commonly used drugs, including aspirin, paracetamol, ibuprofen, codeine and antihistamines, do not work in around a third of people who take them. Millions, for example, do not find codeine an effective analgesic as they have a particular variant of a gene (called CYP2D6) which means they are unable to convert codeine into its active form, morphine.
Another example is the cytochrome P450 family of liver enzymes which are involved in the way our body processes up to 60% of prescribed drugs, and many herbal remedies (eg St John’s Wort). These enzymes vary tremendously between individuals so that some people metabolise these drugs poorly, while others metabolise them very quickly. In the future, knowing your CYP450 gene profile will show whether or not a particular drug will suit you, and whether you need a high or low dose for an optimum result. Although this sounds futuristic, the technology is already available to screen for over 100,000 SNPs, and predict how you will react to certain drugs – whether you will have a good response, a bad response or even no response at all. It is only a short step before your GP checks your DNA before offering you a prescription. Truly personalised medicine is on its way and will allow prescribing to become less of an art and more of a science.
SNPs have been identified that show who will and will not respond to certain:
- cholesterol lowering drugs
- migraine treatments
- anti-psychotics used in schizophrenia
- medicines for heart rhythm disorders
- anti-asthma treatments
- drugs for Alzheimer’s disease
- anti-clotting drugs
Supplements and health
Your genetic make-up means you will respond to supplements in different ways, too, as your genes dictate how well you absorb each nutrient, and how your body processes and eliminates it. One of the most obvious areas to observe these differences is in the treatment of joint pain – one reason why so many different supplements are available.
Some people find glucosamine sulphate alone helpful to reduce joint pain, while others need the addition of other substances such as chondroitin, MSM (methyl-sulphonyl-methane) and/or vitamin C for optimum results. Just as when finding whether you respond best to aspirin or paracetamol, you may need to chop and change to find the right supplement combination, and the right amounts, for your particular symptoms.
As taking glucosamine alone is one of the cheapest options, I usually suggest someone starts with this first. Then, if they are not entirely happy with the response after 2 or 3 months, they can move up a level and combine glucosamine with chondroitin, or MSM, or both. If you are satisfied with glucosamine plus chondroitin alone, then there is no particular need to take MSM too. If you are feel there is still room for improvement you could add in MSM to see if this provides additional benefit.
If inflammation is a particular problem, you might also consider omega-3 fish oils, green-lipped mussel extracts or Devil’s Claw. It is not always obvious which supplements will suit which people so you may need to experiment with combinations to find the right one for you. This will not always be the same combination that suits your friends and neighbours.
Which supplement is right for you?
An estimated one in two adults take a vitamin supplement, but when you’re facing a wall of products, it’s not always easy to know which one to buy.
If your diet isn’t as good as it could be, then a multivitamin and mineral that supplies around the daily recommended intake of as many micronutrients as possible can act as a nutritional safety net. Whichever supplements you choose, make sure they are produced to pharmaceutical standards (known as GMP in the UK and CGMP in the US, which stands for Current Good Manufacturing Practice). This means the supplements and their ingredients are checked at all stages of production for purity and consistency of dose.
Diet should always come first, but national dietary surveys consistently show that significant numbers of people do not meet the recommended intakes for particular vitamins and minerals. There are many reasons why your diet may lack particular micronutrients, ranging from poor appetite and difficulty chewing, cutting back on food to lose weight, or avoiding certain foods because of dislikes, intolerances, ethical, religious or health reasons.
Select nutrients based on your needs
Some supplements contain a carefully selected blend of vitamins and minerals aimed at maintaining a particular body part or function.
Antioxidant blends containing vitamin A, vitamin C, vitamin E and mineral selenium are popular to protect cells from the damaging particles known as free radicals which are associated with age-related conditions such as heart disease and premature wrinkles.
Supplements to support eye health tend to contain research-based blends of antioxidants, B vitamins, carotenoids (lutein and zeaxanthin), zinc and omega-3 fish oils, while supplements designed for women over the age of 50 tend to include calcium, magnesium, vitamin D, vitamin K and sometimes boron to help maintain healthy bones. Vitamin K2 is particularly useful as it reduces the chance of excess calcium being deposited in artery walls.
Single nutrients for specific needs
While most people would benefit from a blend of vitamins and minerals, sometimes single nutrients are recommended or prescribed to treat or prevent an identified deficiency such as:
- iron or vitamin B12 to treat anaemia
- vitamin C to reduce recurrent infections or even scurvy
- Folate to reduce the risk of developmental abnormalities during pregnancy, or folate deficiency anaemia
- Vitamin B6 to reduce premenstrual tension
- Vitamin D to boost immunity, calcium absorption and to prevent bone disease (rickets and osteopenia)
- Magnesium to relax muscles and ease cramps, constipation and aid relaxation and sleep.
While diet should always come first, a significant number of people do not get all the vitamins and minerals they need from their food. If you know your diet is not as good as it could be, a multivitamin and mineral is an excellent choice. During winter months, additional extra vitamin D may be advisable, depending on where you live.
If you mix and match supplements it’s easy to obtain too much of certain micronutrients (eg vitamin A, iron or magnesium) which can lead to toxicity in excess – check tolerable upper safe levels here.
If you are taking any prescribed medication, or if you are in doubt about what you need, always check with your doctor or with a pharmacist.
Do you take any vitamin or mineral supplements? If so, which ones did you select, and why?