Sugar tax among anti-diabetes steps needed

Mike Berridge.
Mike Berridge.
Pure, white and deadly: is the sugar-driven diabetes epidemic unstoppable, asks Mike Berridge, of Wellington's Malaghan Institute of Medical Research.

John Yudkin, British nutritionist and 1972 author of Pure, White and Deadly, who sounded the alarm on sugar and poor health when I was a postdoc at Purdue University, Indiana, and then a scientist at the National Institute of Medical Research in London, was ridiculed and his reputation ruined by the highly politicised and now scientifically flawed anti-cholesterol anti-saturated fat bandwagon.

Today, in a tragic real-life opera being played out in the World Health Organisation (WHO), sugar has replaced fat as the villain, and Dr Yudkin is the hero.

Diabetes is inextricably linked with overweight and obesity, as well as cardiovascular and chronic inflammatory diseases.

Type 2 diabetes (90-95% of diabetics) is initiated and driven by high blood sugar and is reversible.

Simple sugars like sucrose, fructose and glucose are rapidly absorbed into the bloodstream early in digestion.

Refined and processed carbohydrates like white bread and potato starch are absorbed a little more slowly, while complex carbohydrates can be considered "slow-release'' foods subjected to days of intensive digestion in our 8-9m of gut, aided by diverse friendly microbes, the rapturous chorus in this ongoing opera.

Although sucrose is broken down to glucose and fructose, glucose is the main villain, because it initiates pancreatic damage, blunts insulin production and compromises tissue response to insulin through fat accumulation.

This increases blood sugar levels, which remain high for prolonged periods, not just for a couple of hours around mealtimes.

High blood sugar provokes unwanted metabolism, causes oxidative stress and chemically modifies proteins, resulting in deterioration of body tissues.

This explains 43% of cardiovascular disease as well as connective tissue and muscle deterioration.

Tissue damage leads to blindness, kidney failure, limb amputation and early death, all hallmarks of diabetes.

High sugar consumption also plays havoc with the brain and nervous system both directly and indirectly.

Recent experiments show a high sugar diet is as stressful as extreme early life stress and that complex foods the body has to work hard to digest generate a healthy microbiome that promotes immune system and brain health.

Diabetes in New Zealand parallels world trends.

Cases worldwide have quadrupled over the past 35 years to 422million in 2014, and deaths from diabetes have doubled over that time.

Childhood obesity, closely linked to diabetes, is rising at an alarming rate and in New Zealand is highest in Maori, Pacific Island and Indian children and is rampant in lower socioeconomic groups.

The link between poor diet, high blood sugar and diabetes is scientifically sound and has elicited a plan of action in New Zealand, in other countries such as the US and UK and through the WHO.

The WHO Commission on Ending Childhood Obesity, which reported to the director-general in January, is co-chaired by Sir Peter Gluckman who also advises our Prime Minister on science issues.

Targeted approaches are combined with broad population-based initiatives that provide information on diet, exercise and healthy lifestyles to schools and the community, and encourage the food industry to partner in these approaches.

Missing from the New Zealand Government's plan, but recommended by the commission and about to be introduced in the UK, is the strong disincentive of a tax on sweet sugar-loaded drinks.

This has been shown to lower sugar consumption in other jurisdictions and has popular support here in New Zealand.

Arguments by Prime Minister John Key and Health Minister Jonathan Coleman that there is no evidence taxation lowers obesity fall flat in the light of strong scientific evidence that dietary sugar causes type 2 diabetes which is linked to obesity, as well as a plethora of other health problems, including dental decay.

We simply do not have the luxury of time to wait while more people pass the health threshold into a state of sugar-driven diabetes.

Waiting for empirical certainty on which measure may work best falls into the trap of assuming there is a silver bullet.

There is not.

We must supplement the 22 "soft'' measures in the childhood obesity plan with a strong progressive tax on sugar-added drinks and the removal of GST from fresh fruit and vegetables.

This would accelerate current approaches and almost certainly be highly cost-effective in the medium to long term.

Mike Berridge is a Distinguished Research Fellow at the Malaghan Institute of Medical Research in Wellington where he heads the Cancer Cell Biology Group and explores energy metabolism in cancer and in the brain. He speaks on Saturday at the Aspiring Conversations festival of ideas in Wanaka on "Moods, microbes and the gut''.

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