Dr Dingle's Blog / epigenetics
Since the 1980's, there has been a growing amount of research toward the potential interaction between these environmental estrogens and wild animals, with a number of reports detailing the emergence of 'feminised wildlife’ around the world, and a range of adverse effects in humans including decreased sperm count, increased cases of testicular cancer and testicular abnormalities, increased breast cancer in men and women and premature or precocious puberty. Other adverse health outcomes linked with EDC’s include headache, migraine, depression, gastrointestinal disturbances, insomnia, changes in breast tissue and in vaginal bleeding. More chronic symptoms affect the cardiovascular system, the skin (itching, rash, abnormal pigmentation), the gallbladder, and tumours particularly of the breast but also uterus, cervix, vagina and liver. While other studies have shown increases in the organ weight of estrogen-sensitive tissues such as the uterus, and calcium and bone metabolism are all examples of the estrogenic effects. Even how we age and age at menopause can be affected by these chemicals. In support of this at least one professional and very conservative group, the Endocrine Society, has concluded that sufficient evidence now exists linking endocrine disrupting chemicals (EDCs) to adverse human reproductive effects, including possible epigenetic and trans-generational effects.
Unfortunately, our babies are being born pre-polluted with chemicals detectable in their blood, in the placenta and in amniotic fluid because of exposure to these chemicals during pregnancy and throughout the mother’s life. The placental barrier has been shown to allow these chemicals to cross, as many of them have been measured in human fetal cord blood, fetal serum, human amniotic fluid and even newborn stools (meconium). Exposure to these chemicals before birth poses a serious health risks to developing fetus, infants and young children as shown by the increasing adverse effects including negative birth outcomes, childhood obesity and increasing intellectual disabilities. It is believed that current levels of environmental estrogen exposure results in lower birth weights, smaller head circumferences, poorer neuromuscular maturity and visual recognition, delays in psychomotor development, short term memory problems, and growth retardation in newborn babies. Fetal exposure to these environmental estrogens are suspected of disrupting thyroid functioning, sexual differentiation of the brain in foetal development and cognitive motor function and cause anxious behaviour. They are also able to bind to neurotransmitters such as epinephrine, neuroepinophrine and dopamine enabling estrogens to influence the body's central nervous system (CNS). Environmental estrogens have also been shown to effect the body’s immune system.
Studies have found strong links with exposure to excessive levels of estrogen in males with penis abnormalities, lower libido, congenital anomalies, failure of the testes to descend and testicular cancer, reduced penis size and increased embryo mortality.
What is most concerning regarding control of these chemicals is that there are no indications given or regulations set regarding the minimal age at which they should be used or exposed to them. Increasingly, pregnant mothers, infants, pre-pubescent and pubescent children are being exposed to a large number of products containing these chemicals, with no research to show that exposure is safe during these critical periods of development.
Equally strong is the evidence that these same chemicals can cause some of the most common cancers: prostate and testicular cancer in men and breast cancer in women. One of the most troubling is their association with breast cancer. Breast cancer is the major cancer affecting women in the Western world and one of the most disturbing and well documented current trends is the alarming increase in breast cancer incidence over the past few decades. Fifty years ago the risk rate was one woman in 20; today it is one in 8 and approximately two-thirds of breast tumors are estrogen receptive, and environmental estrogens like parabens, phthalates and BPA are known to bind to estrogen receptors. Estrogen-dependent cancers, such as breast cancer, are known to be highly responsive to estrogens for growth. Even more disturbing is the increase in numbers of young girls developing breast cancer.
Genetic determinism—that is, the notion that “it’s all in the genes,” that everything is determined by our DNA and that we are victims of our hereditary—is just not right. You and your conditions, including weight gain and obesity, are not determined by your DNA. In studies of separated twins of obese parents, children growing up in a thin family are more likely to grow up thin. If they grow up in an overweight family they are more likely to be overweight. It appears that while genes have a role in weight gain, it is the passing on of eating habits that are more important.
In recent years, a new idea has come to the forefront of genetics and is the focus of thousands of studies: epigenetics. It is now understood that obesity and weight gain and all the chronic diseases are linked to epigenetic triggers. The vast majority of conditions leading to weight gain are a result of complex interactions between genes and the environment; these interactions cannot be explained by classic genetics.
It is true that the genes we are born with may have an association with weight gain and disease, but this does not prove causation. The truth is only a very small number of people have “smoking gun” genes which predispose them to obesity, diabetes and heart disease. Although heritability is considered to be a major risk factor for weight gain and obesity, the almost 40 candidate genes identified by gene studies (GWAS) so far account for only five percent to 10% of the observed variance in body mass index in human subjects. Other research suggests that heredity may be responsible for less than one percent of the obesity crisis. All the genes combined explain a maximum of 0.9% of variation in human body mass index. So, if it’s not in the genes…
Epigenetics provides the missing link between our environment and weight gain as well as all the chronic illnesses we suffer. Your genes are always responding, in good or bad ways, to what you eat, environmental toxins, your emotions, your stresses and your experiences, and to the nutritional microenvironment within each of your body’s cells. Environmental factors are capable of causing epigenetic changes in DNA that can potentially alter gene expression and result in weight gain and obesity or the opposite. Environmental influences—including nutrition, behaviour, chemicals, radiation and even stress and emotions—can silence or activate a gene without altering the genetic code in any way. These changes in gene expression, the so-called “turning on” of a gene, occur without any change to the DNA sequence.
Each nutrient, each interaction, each experience can therefore manifest itself through biochemical changes, which may have effects at birth or 40 years down the track, or even in the next generation or two. Some of the most well known studies linking epigenetics and obesity have involved the “Agouti” mice. A short-term dietary intervention in pregnant agouti mice, in the form of supplements of folic acid, vitamin B12, choline and betaine, has shown long lasting beneficial influences on the health and appearance of the offspring for multiple generations. The mice that did not get the nutritional supplementation became obese and developed the equivalent of metabolic syndrome and diabetes.
The GOOD news is that, while epigenetic changes can lead to an increase in weight gain and obesity, understanding epigenetics puts us in control. Not only can we avoid outcomes that were once thought of as “in our genes,” but also research is showing that, by changing our diet and lifestyle, we can reverse many of these conditions. Just as the genes for weight gain can be turned on, they can also—with the right information and actions—be turned off. Numerous studies have shown that changing our diet, lifestyle and environment alters our DNA. We are now in control.
Weight gain is not just a fluke; it is a symptom of Western diet and lifestyle—our thoughts and actions being out of balance with our genetics and evolution. As incredible as this may sound, the ability to modify behaviour of your genes to influence weight loss is a key concept in this book. Epigenetics is the scientific field that looks at how genes interact with our diet, environment, lifestyle and even emotions, to change the expression of our genes for better or worse—and in the case of weight gain, for worse.
In a very real sense, everything that happens in our bodies ultimately takes place on a genetic level. Nothing happens without the genes being involved, either directly or indirectly. And the way our genes are programmed is largely a product of our environment and our evolution. A large body of research clearly shows that good health, abundant energy and weight management all rely on the normal functioning of genes which, in turn, depends on a healthy environment, diet and lifestyle. The research also shows that you can improve your weight and health, regardless of the genes with which you are born. You are not stuck with genes that make you gain weight.
Many of today’s health problems result from what amounts to a collision between ancient genetics and modern, highly processed foods. Our genes are routinely exposed to genetically unfamiliar foods and chemicals, and they respond abnormally, such as by triggering inflammation, chronic illness, low energy and weight gain. We evolved in a rich environment full of nutrient-dense foods and only the stress of the hunt—a very different scenario than our lives today. In times past, every calorie consumed came with large amounts of vitamins, minerals, proteins and healthy fats, relatively little starch and almost no grain. Many ancient diets were extraordinarily diverse, including up to a hundred different types of plant foods, as well as scores of land animals, many species of fish and wild bird eggs.
Today, we are living out of balance, and paying the price. It doesn’t take much to put on extra weight. Even small disturbances in energy balance may lead to the onset of obesity.