Posts

Obesogens

Are the chemicals in your environment making you fat?

 

By Tamzyn Murphy Campbell

BSc, BSc Med(Hons) Human Nutrition and Dietetics, RD

 

South Africans rank third fattest in the world after the Americans and British, according to Compass Group Southern Africa’s 2011 report.[1] And while we all know that diet and lifestyle are largely to blame, few realise that insidious little fat-making molecules permeating our environment are making the battle against the bulge even harder.

 

FAT-INATORS

“[The obesity pandemic trend] is more akin to an infectious disease, a contagion, or some other mass environmental exposure [than]… purely a mass alteration in behaviour change” – Professor Lustig, paediatric endocrinologist at the University of California.[2]

Indeed, recent evidence indicates that various environmental hormone-disrupting chemicals increase the number of fat cells and their storage, thereby promoting obesity.[3] These obesogens can also boost appetite and reduce feelings of fullness, increasing the calories you consume.[2] Plus they can shunt the calories you eat into storage rather than allowing them to be burned as energy. [2] Exposure to obesogens in the womb and during early development could increase fat cell quantity for life and programme you for future obesity, even if the exposure is short-lived.[3]

Despite this field being so new, scientists know of at least 20 obesogens. Some of which have been found in 95% of the American population; implying that chemical exposure has the potential to affect most if not every member of a population.[4]

 

ESTROGENS

They’re everywhere. In our water, food and plastics. Possibly our biggest environmental estrogen exposures are DDT, bisphenol-A (BPA) and genistein.[2] DDT use as a pesticide has ceased worldwide with a few exceptions. However, it’s still used indoors in countries including South Africa to reduce malaria.[5] DDT is detrimental to health, specifically reproductive health and has been implicated in diseases like cancer.[6] In the US, where it’s been banned since 1972, DDT’s metabolite DEE is still being found in pregnant women’s urine, even in those born after 1972. Pregnant women’s urine-DEE concentration predicts the weight of their children at age three.[2]

BPA (in hard plastic bottles numbered ’7’, babies’ bottles and toys and the plastic lining of tins) is also linked to cancer, reproductive changes,[7] fat cell production and increased adult body mass index (BMI).[2]

Newborn rats given genistein (from soya and alfalfa) were fatter at age three and four months. It’s not known whether genistein contributes to human obesity. Though it’s possible the large amount of soya commonly found in our food supply is cause for concern.[2]

 

OTHER OBESOGENS

  • Pthalates are plasticisers that make plastics soft and pliable and have a distinctive new-plastic smell. They’re in hundreds of products from cling wrap and beverage bottles[8], to shower curtains, raincoats and children’s rubber duckies. [9],[2] They’re even in personal care products[9]. Everyone’s contaminated. Recently, urine phthalate levels have been linked to increasing waist circumference[2]
  • Atrazine and other organochlorines Atrazine is a widely used pesticide and it’s teratogenic, meaning it causes malformations during pregnancy. Blood atrazine levels are linked to fat stores and insulin resistance in adults[2]
  • Tributylins (TBT) and other organotins TBT is used to paint boats’ hulls to keep them barnacle free. So it’s also in our general water supply. TBT tells fat cells to multiply, boosts dangerous belly fat (via the hormone cortisol), and promotes fatty liver in infant rats whose pregnant moms were exposed to TBT once. Scientists know we’re exposed to TBT because it’s found in our urine, but still need to confirm if it’s a primary cause of human obesity[2]
  • Cigarettes and air pollution are both linked to weight gain and obesity in studies. In children, thiocyanate (cyanide’s cousin) from second-hand cigarette smoke reduces thyroid hormone levels (responsible for metabolism). And traffic within 150 miles of a child’s home appears to increase BMI at age 18.[2]

 

DAMAGE CONTROL

If you’ve been exposed to obesogens, particularly before puberty, your metabolism’s adjusted to be more efficient at storing fat. So, is this an excuse to give up your lifelong weight battle? Dr Bruce Blumberg, professor of developmental and cell biology at the University of California, Irvine, who coined the term ‘obesogen’ back in 2006, says that exposure doesn’t ensure obesity. It just means you have to try a little harder.[4]

It’s probably best to copy Dr Blumberg’s strategy to minimise his and his family’s obesogen exposure: reduce plastic in your life; avoid sugar (for more on this read Lustig article on page X) and processed, canned and packaged food; and eat organic, fresh, home-made food whenever possible. [4]

 

References include

[1] South African Institute of Race Relations. Press Release. African women and white men weigh in heaviest. Feb 2013

[2] Lustig RH. Fat Chance. Hudson Street Press, London, England. Jan 2013

[3] Grun F, Blumberg B. Endocrine disruptors as obesogens. Mol Cell Endocrinol. May 2009;304(1-2):19-29 http://www.ncbi.nlm.nih.gov/pubmed/19433244

[4] Ahearn A. What do we know about obesogens? with Bruce Blumberg. Environmental Health Perspectives. Jul 2012;120. Published online http://ehp.niehs.nih.gov/july-podcast/

[5] South Africa.info. WHO follows SA’s lead on DDT. Sep 2006 http://www.southafrica.info/about/health/malaria-190906.htm#.UahjMECmg1I

[6] US Environmental Protection Agency. Persistent Bioaccumulative and Toxic (PBT) Chemical Program. DDT. Apr 2011 http://www.epa.gov/pbt/pubs/ddt.htm

[7] Breast Cancer Fund. Bisphenol A (BPA). May 2013 http://www.breastcancerfund.org/clear-science/chemicals-glossary/bisphenol-a.html

[8] Sax L. Polyethylene terephthalate may yield endocrine disruptors. Environ Health Perspect. Apr 2010;18(4):445-8  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2854718/pdf/ehp-118-445.pdf

[9] Centers for Disease Control and Prevention. Factsheet: Pthalates. Apr 2012 http://www.cdc.gov/biomonitoring/Phthalates_FactSheet.html

 

Inflammatory food

Excess inflammation leads to autoimmune, inflammatory and age-related diseases as well as aging, but changing the way you eat can help

By Tamzyn Murphy Campbell
BSc, BSc Med(Hons) Human Nutrition and Dietetics, RD

Excess inflammation leads to autoimmune, inflammatory and age-related diseases as well as aging, but changing the way you eat can help

By Tamzyn Murphy Campbell
BSc, BSc Med(Hons) Human Nutrition and Dietetics, RD

To most of us “inflammation” – characterised by redness, heat, pain and swelling – is a dreaded word associated with a variety of ailments: joint pain, backache, arthritis, inflammatory bowel disease and psoriasis (skin condition). But inflammation actually has an essential role to play. It’s our body’s first form of attack against infection or other foreign bodies. The wellknown inflammation related problems set in when inflammation spirals out of control and starts to attack the body’s own tissues – autoimmune disease – or when it goes on too long – thought to be one of the processes responsible for aging and related diseases. So, although inflammation is an important indicator of something being wrong, keeping it in check and preventing it from going overboard is fundamental to health – and what you eat can help.

BEAT THE BELLY

Belly fat releases inflammatory molecules which scientists blame for obesity-associated inflammatory diseases: insulin resistance, diabetes and heart disease risk factors (high blood pressure and imbalanced blood fat and cholesterol levels). It’s also linked to lower levels of the hormone adiponectin, which may play a role in increased inflammation, heart disease risk and insulin resistance. Research indicates that women with a belly have more signs of inflammation than their male counterparts. Scientists have found that using diet to keep weight in check reduces inflammation and the markers of its associated diseases. So find a diet and exercise program that works for you, and stick to it to drop the kilos and keep inflammation free. Reducing stress and getting adequate sleep can also help keep the belly at bay.

INFLAMMATORY FOOD

Researchers have found that certain food promotes inflammation, while other food reduces it. Avoid the following to reduce inflammation:

  • Trans fats – found in processed baked goods (biscuits) and fast food fried in reused oil – raise inflammation-boosting molecules and heart disease risk
  • Refined carbohydrates and sugar increase inflammation, probably due to the combination of their low fibre, vitamin, mineral, phytonutrient and essential fatty acid content, as well as their penchant for swinging blood sugar and insulin levels. This boosts blood fat and free radicals, causing inflammatory molecule production, which in turn results in inflammation
  • Processed food is high in trans fats and refined carbohydrates and sugar. So they’re definitely a no-no
  • Excess omega-6 fats Most of us get too much inflammation-promoting omega-6 in our diet, from processed food and cooking oils, like sunflower oil. The omega-6 fat, linoleic acid (LA) is converted into arachidonic acid (AA), which is the major building block for making inflammation-promoting molecules (eicosanoids).

ANTI-INFLAMMATORY FOOD

This food helps reduce inflammation throughout the body and therefore also age-related inflammatory diseases (e.g. osteoarthritis) and the activation of aging genes

  • Unsaturated fats Monounsaturated fats from nuts, seeds, avocado, olive and canola oils improve your blood fat profile to reduce inflammatory molecules and heart disease risk
  • Omega-3 fats found in oily fish (Norwegian salmon, snoek, sardines, anchovies), activate anti-inflammation genes. They’re also a building block for the production of anti-inflammatory molecules. And higher levels of omega-3 fats inhibit the production of inflammatory molecules made from omega-6 fats. Eat fatty fish at least three times per week or supplement with fish, or krill oil
  • Moderate alcohol has been linked to lower blood levels of inflammation-promoting molecules and reduced heart disease risk. Wine (1-2 glasses daily) is particularly anti-inflammatory, but beer and liquor have also been found to be beneficial
  • Antioxidants found in fruit and vegetables (especially brightly coloured ones), certain herbs and spices (cloves, oregano, rosemary, tumeric), green and rooibos tea, dark chocolate and red wine reduce free radical damage and inflammatory molecule production
  • Fibre exerts its anti-inflammatory effects by helping control blood sugar, insulin, fat and cholesterol levels, increasing adiponectin levels and reducing inflammatory molecule production. Fibre’s found in vegetables, fruit, beans, lentils, nuts and seeds.

References include

  1. Chung HY, Lee EK, et al. Molecular Inflammation as an Underlying Mechanism of the Aging Process and Age-related Diseases. JDR. Jul 2011;90(7):830-40
  2. Pou KM, Massaro JM, et al. Visceral and subcutaneous adipose tissue volumes are cross-sectionally related to markers of inflammation and oxidative stress. The Framingham Heart Study. Circulation. 2007;116:1234-41
  3. Giugliano D, Ceriello A, et al. The effects of diet on inflammation. Journal of the American College of Cardiology. 2006;48(4):677-85
  4. Lihn AS, Pedersen SB, Richelsen B. Adiponectin: action, regulation and association to insulin sensitivity. Obes Rev. Feb 2005;6(1):13-21
  5. Tajik N, Keshavarz SA, et al. Effect of diet-induced weight loss on inflammatory cytokines in obese women. J Endocrinol Invest. Jun 2012: Published online
  6. Calder PC. n−3 Polyunsaturated fatty acids, inflammation, and inflammatory diseases. Am J Clin Nutr. Jun 2006;83(6):S1505-19
  7. ORAC Values. www.oracvalues.com. Jul 2012