Nutrigenetics

Genetics is getting personal…and applied to nutrition

We are all different and this is mainly due to our genes. There are the differences that we all see like eyes and hair colour, but then there are the differences inside – how we metabolise nutrients for example, the way we deal with toxins – we all interact with the environment in our own unique way. Genetically we are almost identical, but in each gene there are points of variation, the most common type being a single base change at a particular position – this variation is called a Single Nucleotide Polymorphism, or SNP (pronounced SNIP). It is the collection of these small differences that affect who we are and define our individuality – but genes are not all, they don’t work alone and they don’t determine everything about us. Genes interact with our environment – and modifying the environment modifies our “phenotype” – the way we are (e.g. a fair skinned person will only suffer from sunburn if she/he stays in the sun too long). Because we have some control over our environment we can have some control on our destiny, we are not slaves to our genes, and the biggest “environment” is our diet, the food that we eat.

A healthy diet contributes to a long and healthy life, but exactly what is a healthy diet? Is it the same for everyone? No. One size does not fit all and one diet, or one “Recommended Daily Dose” does not suit all. 

Over the last 10 years enormous progress has been made in the area of gene-environment interactions and a new field of knowledge has emerged: Nutrigenetics. This knowledge is ready to apply right now for the benefit of your clients. We have used it to design a panel of genes that determine how individuals handle certain key diet components. The panel will shape the diet you give to your clients, tailoring it to his / her genotype, determining the daily goals of nutrients and the daily limits of components such as saturated fats. Each piece of genetically derived advice delivered in the personal NutriGENE report is the fruit of repeated scientific studies by different labs around the world and published in peer reviewed international journals. There is an enormous body of scientific literature that details how individual genetic variation can affect your dietary needs.

Genes modify your nutritional requirements and NutriGENE determines the personal goals and limits that are needed by each of your clients. A simple genetic test reveals the variations in 20 relevant genes; the results are converted to a personal report and nutrient goal chart. The report explains to you and your client what each of the genetic variations means to him/her and the nutrient table makes it easy to design a personal diet with optimum amounts of important components – this will be “your clients diet” and no-one else’s. It’s not a radical diet, but is made up of small modifications in various areas – small modifications that over the long term can have a very significant effect on health and well being. Did you know that just 20 calories per day in excess, that’s a teaspoon of sugar, can cause a weight gain of 12 kg over 20 years – easy to put on, very hard to get off. But think then what a little bit too much saturated fat might be doing over the 20 years as well…then your client will start to understand the potential benefits of a personalised nutrigenetic diet. 

Knowing that the diet is personal, knowing how the genes work and how they modify what we need - knowing thyself - is a powerful motivator. 

NutriGENE™ -  

OVERVIEW 

Personalised diet and lifestyle

The basis for the a new dietary and lifestyle that will determine the nutrient goals for many essential components such as folic acid and other vitamins and minerals. It will also determine the advised upper limits of dietary components such as saturated fats, caffeine, salt, etc. 

NutriGENE™ analyses genetic variation in 20 genes that interact with diet and lifestyle. It is not a diagnostic test nor is it a risk analysis – it will not reveal any genetic diseases, all the genes tested have very common polymorphisms, it does not reveal “bad” genes, just different versions of genes. We do not test for rare genetic diseases. All of the genes included interact in some way with the environment, usually with dietary components – the body is very complex and genes do not act on their own, they produce proteins that are one part of a multi-component system that maintains the homeostasis of the organism. Genes and environment (diet, lifestyle, air quality, stress levels, type of work, etc) work together and can affect our health in both positive and negative ways. A person’s genotype is fixed at conception but the environment can be modified. By a) knowing the genotype (i.e. the particular version of a gene) and b) understanding how it interacts with the environment, it is possible to modify the latter to promote optimum health and well-being. 

An example is the Lactase gene and lactose intolerance. In Europe there are predominantly two very common versions of this gene, one leads to lactose tolerance, i.e. it remains possible for the individual to consume lactose rich foods (mainly dairy produce) throughout adult life since he/she continues to produce the lactase enzyme in high levels and this is the enzyme which digests lactose, the sugar found in milk. The other version of the gene leads to lactose intolerance – infants can digest lactose but as they get older, usually between 5-8 years old, the gene that produces lactase slows down, much less enzyme is produced and lactase is not digested properly. It is utilised by bacteria in the intestines, creating a type of fermentation process and gas production which causes mild to severe gastric symptoms in the affected person. The important point about lactose intolerance is that it is only a problem when lactose containing products are consumed – as long as no, or only small amounts of, lactose are consumed then the individual can lead a perfectly normal life, in fact lactose intolerance is the normal state – the vast majority of the world’s population can only tolerate lactose during the early years of infancy, while feeding on the mothers milk. The variation that leads to lactose tolerance (also called lactose persistence) appeared relatively recently in human history and in is present almost entirely in people of middle European origin – in Italy for example lactose intolerance is very widespread, averaging about 50% but depends on the region.

Another gene tested is MTHFR – this is involved in pathways which metabolise folic acid and utilise vitamins B6 and B12 and which are closely involved in homocysteine levels. There is a very common variant, 677T - present in approx. 40% of the Italian population – which produces an enzyme that works much more slowly than the other version, 677C. Many, many studies have shown that people with the T variant, especially if they are homozygous 677TT (i.e. they received the same T version from both mother and father) require higher levels of folic acid in order to keep homocysteine levels within the normal range (homocysteine is a biomarker that is assessed as a risk factor for cardiovascular diseases). The recommended daily intake of folate acid is 200 µg in Europe and 400 µg in the USA. Several intervention studies have shown that these levels are not adequate to maintain normal levels of homocysteine so these individuals are advised to consume at least 600 µg per day plus higher levels of vitamins B6 and B12, whereas for those with the 677C version, 300µg is recommended. 

Other genes analysed in the NutriGENE™ are involved in various metabolic systems including lipid metabolism (saturated fats, MUFA, PUFA, cholesterol), removal of oxidative stress products, removal of toxins (e.g. from airborne pollution, cigarette smoke, grilled meat, etc), glucose and insulin control, inflammatory processes, utilization of vitamin D and calcium. The SLC6A4 gene (serotonin transporter) is an important component of the NutriGENE™. Two common forms are the L and S versions (Long and Short) and vary by the length of a region in the gene called the promoter (this region controls the activity of the genes). This genetic variation has been associated in many studies with stress and particularly with how an individual copes with various levels and types of stress. It has been shown that those with the S version are less likely to be able to cope rapidly with stress events – for example a study in nurses (a job with many stressful events) showed that disturbed sleep was more common in those with the SS genotype compared to LL individuals. Diet has been shown to be both a contributor to stress (e.g. starting a weight loss diet can be stressful) and also be able to control responses to and coping with stress. Depending upon genotype, individuals will be given a comprehensive list of foods they should use for their nutrition and also any supplements that maybe appropriate to take. Lifestyle methods of improving ability to cope with stress and reduce the incidence of stressful events are important factors in any lifestyle program.

*There are also several genes that have been included to determine the predisposition for celiac disease. These genes will not diagnose the presence of celiac disease but they are useful to exclude celiac disease as a possible cause of any gastro-intestinal symptoms such as irritable bowels, etc. 

Heart Health Genetic Variations 

We know that genes serve as the blueprint for the construction of the critical protein components that carry out the work of all the cells in our bodies. What we're learning thanks to advances in nutrigenomics is what happens when you have a variation in a gene, a form that's different from the more common version. Further, scientists are very interested in which gene variants are associated with diet and lifestyle choices. The reason for the interest is that it then becomes possible to adjust those choices to help a gene variation do a better job by matching our choices to the particular variants we have. In terms of heart health, several genes are known to be important to heart health AND to be associated with diet and lifestyle choices, such as APOC3, LPL, MTHFR and IL6. The first two genes are involved with regulating the level of potentially harmful fats in our blood. Particular variants in these genes can lead to higher levels of fats in our blood than are considered healthy for long-term heart health. The MTHFR gene is involved in B vitamin metabolism. A variation in this gene leads to a buildup of homocysteine, which can irritate the lining of the blood vessels throughout the body and set the stage for cardiovascular disease. Food and dietary supplement choices can lower homocysteine levels and, potentially, counteract its harmful effects. The IL6 gene is particularly interesting because it's involved in the body's inflammatory response. Certain gene variants can promote inflammation in the body and lead not only to heart disease but to a number of chronic disorders: arthritis, brain disorders, cancer, diabetes, obesity, and osteoporosis. 

The Heart Health-Homocysteine Connection 

There are many factors that can affect heart health. One that you can likely do something about is how your body handles homocysteine. This amino acid stands out from the rest since it is suspected of being a culprit in atherosclerosis. The exact way this happens is still being studied, but a strong possibility is that high levels of homocysteine in your body can damage the lining of the blood vessels. Once damaged, the vessels are more prone to accumulate plaque and can lead to hardening of your arteries. Homocysteine can also increase the clotting of your blood, which in turn increases the risk of having interfering with oxygen flow to the heart and brain, causing a heart attack or stroke, respectively. 

Homocysteine is part of a never-ending cycle that goes on in each of the cells in our body. New proteins, fats, and carbohydrates are constantly being made and broken down in a stepwise process by which one compound is converted into another. If for some reason one of these conversion steps can't proceed, there's a log-jam effect and the compound behind the log-jam builds up and ultimately spills over into places it shouldn't be, such as the blood. In the case of homocysteine, high levels in the blood lead to inflammation of the blood vessel walls. The good news is that B vitamins, particularly folate, are helpful in breaking the log-jam and allowing the cycle to proceed so that homocysteine levels stay within the normal range. Adequate levels of the B vitamins is essential for everyone but those with the genetic variant of the MTHFR gene need to be extra careful to obtain adequate levels of folate and may need amounts greater than the typical recommended levels 

Gene Variants and Inflammation 

Inflammation plays a major role in the development of heart disease so it's not surprising that some gene variations can increase your susceptibility to both inflammation and heart disease. Genes such as the IL6 gene have been identified as having variants that increase the risk of developing heart disease. Knowing which variants you have for such genes and which dietary and lifestyle choices help to minimize their pro-inflammatory effects can help you in your goal of reducing the risk of heart disease. 

Since inflammation is a strong component of many other chronic diseases as well, information about your particular susceptibility to overall inflammation is likely to become increasingly important for both treating and preventing chronic diseases such as arthritis, diabetes, obesity, osteoporosis and, of course, heart disease. 

One of the variants of the IL6 gene, the -174G>C variant, is particularly interesting. Cigarette smoke stimulates the expression of this gene, leading to increased inflammation. Individuals with this variant will want to be particularly careful to avoid smoking themselves and also to avoid exposure to second-hand smoke. 

Clearly, knowing the variations you have in genes that are influenced by lifestyle choices can be very helpful in making smart choices for your own health.

Attachment:

NEW Nutrigene™
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BROCHURE
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NEW Nutrigenetics and the scientific basis
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NEW Nutrigene™ Overview
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NEW NutriGENE™ Results and Personal Report for SAMPLE
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Alopegiagene®
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NutriGENE™ Results and Personal Report for SAMPLE
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Nutrigenetics key references
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