The rat race towards obesity
20 December 2018 - Shaun Smillie
The fast food generation is trapped in an "obesogenic environment" due to international junk food giants and sugary sweet marketing.
To get out of this trap, we need some out of the box thinking, including looking for answers in traditional medicinal plants.
Hamburgers, a side of chips, and a doughnut for dessert, all washed down with a sweetened carbonated drink.
If the young rats in the Endocrinology and Metabolism Research Lab in the School of Physiology at Wits were the human children they were modelled on, this might have been a typical meal. But these lab rats had consumed a high-calorie fructose [fruit sugar] solution designed to mimic the sugar-enriched Western diet behind the obesity pandemic that is hitting South Africa hard.
The rats were fed a high-fructose diet to test: a possible new weapon in the arsenal against obesity and the metabolic diseases associated with it. Surprisingly, it is a weapon that humanity has known for millennia – it's the Terminalia sericea, the silver cluster-leaf tree, widely distributed in southern Africa.
Traditionally this plant has been used to treat a host of ailments, including intestinal infections, hypertension and diabetes. Studies have shown that the silver cluster-leaf contains chemical compounds that break down fat.
A tree, a rat and liver fat
Intrigued by the plants' ability to break down fat, Dr Busisani Lembede was interested to see whether it could be used to fight the development of non-alcoholic fatty liver disease (NAFLD), the number one liver disease in the world. Fatty liver disease refers to a range of diseases related to a build-up of fat in the liver cells, and the risk of developing it is increased by obesity.
"We speculate that some of these chemicals in the silver cluster-leaf tree may also prevent the deposit of excessive fats in the liver," says Professor Eliton Chivandi in the School of Physiology at Wits.
NAFLD is a growing problem globally and a leading cause of liver damage. An estimated 30 to 40% of the global population has NAFLD. In the United States, 17.3% of children between the ages of 15 and 19 years old have non-alcoholic fatty liver disease.
"There are so many causes of obesity, but in South Africa it is the lifestyle – particularly the dietary component of it that seems to be the main cause," says Chivandi. "People are consuming a lot of sweetened foods with fructose and high in saturated fats, and this contributes to the production of excess calories."
In the lab, some of the rat pups consumed a control (normal) diet, while others consumed the high-fructose diet of either fenofibrate (a conventional pharmacological agent) or extracts from the silver cluster-leaf tree. The scientists found that the extracts from the silver cluster-leaf suppressed fructose-induced liver lipid accumulation and fatty liver disease.
Fat-fighting flora
The silver cluster-leaf tree is not the only traditional plant-derived medicine potentially with properties to tackle obesity. Countries like India and Italy are taking a serious look at plants to see if they can fight fat.
"There are plants such as the Moringa oleifera Lam tree [Moringa tree], garlic, and the common fig with potential health beneficial properties," says Chivandi. Research has shown that people across the globe are more willing to use natural remedies rather than Western medicines, which they perceive as having side effects.
"About 80% of the global population uses traditional medicine. In fact, the World Health Organization says that: more research should be carried out into traditional medicines, as this would reduce the pressure on health facilities," says Lembede.
However, even if the silver cluster-leaf tree proves to be a cure for fatty liver disease, it won't be enough to curtail the obesogenic environment in which we find ourselves. An obesogenic environment is an environment where external influences, opportunities and conditions impact our lifestyles to cause obesity.
An obesogenic environment
"We have an obesity problem and a food security problem," says Wits Professor Karen Hofman, Director of PRICELESS SA (Priority Cost Effective Lessons for Systems Strengthening SA) who co-authored a study on obesogenic environments. "We must not forget that we have 20% of children in South Africa who are still stunted. Yes, we do have an obesity epidemic and it is increasing by the day. But we can't turn back the clock, because the deed is done."
Obesity does not differentiate between the rich and poor. The poor get their fix of the high calorie diet that causes obesity from cheap, processed foods, as healthier food is often more expensive, and out of reach for more vulnerable groups.
"This is not an individual lifestyle choice – it is caused by a concerted effort driven by profit to ensure that countries that can provide a growth target for these companies are subjected to processed foods and beverages that contain often high levels of sugar. This is all about marketing and particularly marketing to children and teenagers," says Hofman.
The majority of South Africans got a taste of this new diet with the dawn of democracy.
Twenty years later and South Africa is the most obese country in sub-Saharan Africa. With this weight-gain has come the highest prevalence of diabetes on the continent. However, it is difficult to work out just how many people have diabetes, as half of sufferers have yet to be diagnosed.
"In 2013, the prevalence of diabetes was 26 cases per 1 000. In the public health sector in 2014, there were 5 000 new diabetes cases a month. By 2016, that was close to 15 000," says Hofman.
It is not just processed foods and sugary drinks that are expanding our waistlines. South Africans, like so many others worldwide, are becoming increasingly sedentary. Chinvandi, who is also a warden at one of the Wits residences, is regularly shocked to see how many delivery bikes deliver fast foods such as pizzas and chicken to students.
"Our students won't walk. They would rather order it. So that shows how sedentary our population has become," says Chivandi.
But exercise alone is not enough to beat the epidemic. "As they say, you can't exercise your way out of a bad diet. And all it does is confuse people," says Hofman, who believes fighting obesity comes down to a holistic approach, with the state taking the lead.
Sugar and the State
The South African government's introduction of a tax on sugar-sweetened beverages in April 2018 was a small victory in the fight against obesity. This 'sugar tax' – officially the health promotion levy – applies a tax of 2,1c for every gram of sugar per 100ml above a 4 gram threshold. Similar fiscal measures applied in other countries have worked.
A 2016 study published in the peer-reviewed BMJ reported that annual sales of sodas in Mexico declined by 6% in 2014 after the introduction of a similar tax. Sugar tax in South Africa could make an enormous difference.
"Nine and 10 year olds in South Africa are the highest consumers of sugary beverages in the world," Hofman says.
Although it is too early to assess the effect of the health promotion levy in South Africa on the sale of sugar-sweetened beverages, Hofman says there has already been one positive effect. In October, Treasury announced that it had collected just over R1 billion in sugar tax revenue between 1 April and 31 August – a significant income considering
R1.64 billion was expected for the entire 2018-2019 fiscal year.
Kids and candy from corporate strangers
Research shows that unhealthy food preferences are established at an early age. Another measure Hofman advocates is preventing corporates from marketing to children. The way that corporations target children can be seen in how supermarkets often place sweets and junk food within eye level of children. Low-placed shelves at checkout aisles are packed tight with chocolates and other sweets.
"Children are repeatedly exposed to marketing [which] portrays unhealthy foods as fun, 'cool', exciting and positive. [Marketers] use promotional packaging, they use celebrities and athletes to endorse their products, they have kid-friendly animations, use child actors, and video games. Billions are spent on targeted marketing to children," says Hofman.
A study found that 50% of schools had Coca-Cola signs on their grounds. This, Hofman points out, was five years after Coca-Cola said it would no longer market to children. Hofman says schools should remove all unhealthy food from their tuck shops.
Labelled for losing
Another measure that could help in the fight against obesity is to improve food labelling.
"Labelling will guide us with choices, as most consumers take less than 10 seconds to select a food item," says Hofman. She believes labels need to be bold and to the point – like the in-your-face warnings on cigarette packets. There is already labelling on some food items but the problem, says Hofman, is that it is often designed to bamboozle customers.
"The global experience tells us that negative, clear warnings are very effective. You need something that tells you, 'this is very high in sugar'. Period. That is all."
This article first appeared in Curiosity, a research magazine produced by Wits Communicationsand the Research Office.
Read more in the sixth issue, themed: #HungerGames where our researchers and academics unpack the latest research on food security, food science, food politics and governance, nutrition and food-related issues such as obesity, diets, breastfeeding, and body image.