Friday, August 14, 2015

Could a sugar tax help combat obesity?

Following the BMA's call for a 20% sugar tax to subsidise the cost of fruit and vegetables, experts in TheBMJ this week debate whether a sugar tax could help combat obesity.
Sirpa Sarlio-Lahteenkorva, adviser at the Ministry of Social Affairs and Health in Finland, says that a specific tax on sugar would reduce consumption. "Increasing evidence suggests that taxes on soft drinks, sugar, and snacks can change diets and improve health, especially in lower socioeconomic groups," she writes.
Taxes on specific food categories that are common constituents of poor diets "are practicable because they are simple to administer," she adds.
However, she acknowledges that taxes can only be a partial solution, and suggests that a sugar tax on all products may be more acceptable "because it would treat all sources equally. It could also stimulate reformulated products, with less sugar and hence liable for less tax."
In Finland, the Sugar Tax Working Group recently concluded that the current system of using excise duty is most practicable. "A combination of excise duty for key sources of sugar with tax adjusted based on sugar content would optimally promote health - and product reformulation."
Nevertheless, Professor Sarlio-Lahteenkorva points out that taxes for health face many challenges, as recently seen with Denmark's short experiment with a tax on saturated fat, which seems to have reduced consumption of fats by 10-15% but worries about border trade and lobbing by industry led to its withdrawal. The food industry also argues that consumption taxes are ineffective, unfair, and damage the industry.
"We need fiscal policies that take health seriously," she writes. "Governments must tackle the related adverse health effects, such as diabetes, coronary heart disease, and hypertension. A tax on sugar, preferably with measures that target also saturated fat and salt, and incentives for healthy eating, would help," she concludes.
But Jack Winkler, emeritus professor of nutrition policy at London Metropolitan University, argues that such taxes would be a positive development in principle, but are politically unpalatable and would have to be enormous to have any effect.
He points out that referendums in the United States have led to soft drinks taxes in just one city (Berkeley), while only four of 53 states in WHO-Europe have adopted food taxes, all with the stated aim of raising revenue, not improving health.
Food taxes are also economically ineffective, he adds. Two rigorous UK studies found that a 10% tax would reduce average personal daily intake by 7.5 mL (less than a sip), while a 20% tax would reduce consumption by 4 kcal. "Effects of this size will not reverse global obesity," he argues.
He suggests that cutting product margins on sugar-free soft drinks would be a positive alternative, which would make the healthy choice the cheaper choice - and would would boost companies' profit.
He points out that before and after the recent UK election, government spokespeople stated repeatedly that there will be no new food taxes and immediately rejected the BMA's proposal.
Why are we still debating this idea, he asks? "Nutrition policy needs price instruments, but a more positive selection. Sugar taxes are unlikely to be adopted and would not make much difference anyway," he concludes.
Link to article

Trans fats, but not saturated fats, linked to greater risk of death and heart disease

Higher trans fat intake associated with 20-30% increased risk, say researchers

Saturated fats are not associated with an increased risk of death, heart disease, stroke, or type 2 diabetes, finds a study published in The BMJ this week. However, the findings show that trans fats are associated with greater risk of death and coronary heart disease.
The study confirms previous suggestions that industrially produced trans fats might increase the risk of coronary heart disease and calls for a careful review of dietary guidelines for these nutrients.
Guidelines currently recommend that saturated fats are limited to less than 10%, and trans fats to less than 1% of energy to reduce risk of heart disease and stroke.
Saturated fats come mainly from animal products, such as butter, cows' milk, meat, salmon and egg yolks, and some plant products such as chocolate and palm oils. Trans unsaturated fats (trans fats) are mainly produced industrially from plant oils (a process known as hydrogenation) for use in margarine, snack foods and packaged baked goods.
Contrary to prevailing dietary advice, a recent evidence review found no excess cardiovascular risk associated with intake of saturated fat. In contrast, research suggests that industrial trans fats may increase the risk of coronary heart disease.
To help clarify these controversies, researchers in Canada analysed the results of observational studies assessing the association between saturated and/or trans fats and health outcomes in adults.
Study design and quality were taken into account to minimise bias, and the certainty of associations were assessed using a recognised scoring method.
The team found no clear association between higher intake of saturated fats and all cause mortality, coronary heart disease (CHD), cardiovascular disease (CVD), ischemic stroke or type 2 diabetes, but could not, with confidence, rule out increased risk for CHD death. They did not find evidence that diets higher in saturated fat reduce cardiovascular risk.
However, consumption of industrial trans fats was associated with a 34% increase in all cause mortality, a 28% increased risk of CHD mortality, and a 21% increase in the risk of CHD.
Inconsistencies in the included studies meant that the researchers could not confirm an association between trans fats and type 2 diabetes. And they found no clear association between trans fats and ischemic stroke.
The researchers point out that the certainty of associations between saturated fat and all outcomes was "very low," which means that further research is very likely to have an important impact on our understanding of the association of saturated fats with disease. The certainty of associations of trans fat with CHD outcomes was "moderate" and "very low" to "low" for other associations.
They also stress that their results are based on observational studies, so no definitive conclusions can be drawn about cause and effect. However, they say their analysis "confirms the findings of five previous systematic reviews of saturated and trans fats and CHD."
And they conclude that dietary guidelines for saturated and trans fatty acids "must carefully consider the effect of replacement nutrients."

Link to article

Regular consumption of spicy foods linked to lower risk of death

Data suggests most benefit from eating spices regularly throughout the week
Eating spicy food more frequently as part of a daily diet is associated with a lower risk of death, suggests a new study published in The BMJ this week. The association was also found for deaths from certain conditions such as cancer, and ischaemic heart and respiratory diseases.
This is an observational study so no definitive conclusions can be drawn about cause and effect, but the authors call for more research that may "lead to updated dietary recommendations and development of functional foods."
Previous research has suggested that beneficial effects of spices and their bioactive ingredient, capsaicin, include anti-obesity, antioxidant, anti-inflammation and anticancer properties.
So an international team led by researchers at the Chinese Academy of Medical Sciences examined the association between consumption of spicy foods as part of a daily diet and the total risk and causes of death.
They undertook a prospective study of 487,375 participants, aged 30-79 years, from the China Kadoorie Biobank. Participants were enrolled between 2004-2008 and followed up for morbidities and mortality.
All participants completed a questionnaire about their general health, physical measurements, and consumption of spicy foods, and red meat, vegetable and alcohol.
Participants with a history of cancer, heart disease, and stroke were excluded from the study, and factors such as age, marital status, level of education, and physical activity were accounted for.
During a median follow-up of 7.2 years, there were 20,224 deaths.
Compared with participants who ate spicy foods less than once a week, those who consumed spicy foods 1 or 2 days a week were at a 10% reduced risk of death (hazard ratios for death was 0.90). And those who ate spicy foods 3 to 5 and 6 or 7 days a week were at a 14% reduced risk of death (hazard ratios for death 0.86, and 0.86 respectively).*
In other words, participants who ate spicy foods almost every day had a relative 14% lower risk of death compared to those who consumed spicy foods less than once a week.
The association was similar in both men and women, and was stronger in those who did not consume alcohol.
Frequent consumption of spicy foods was also linked to a lower risk of death from cancer, and ischaemic heart and respiratory system diseases, and this was more evident in women than men.
Fresh and dried chilli peppers were the most commonly used spices in those who reported eating spicy foods weekly, and further analysis showed those who consumed fresh chilli tended to have a lower risk of death from cancer, ischaemic heart disease, and diabetes.
Some of the bioactive ingredients are likely to drive this association, the authors explain, adding that fresh chilli is richer in capsaicin, vitamin C, and other nutrients. But they caution against linking any of these with lowering the risk of death.
Should people eat spicy food to improve health? In an accompanying editorial, Nita Forouhi from the University of Cambridge says it is too early to tell, and calls for more research to test whether these associations are the direct result of spicy food intake or whether this is a marker for other dietary or lifestyle factors.
* A hazard ratio is a measure of how often a particular event happens in one group compared to how often it happens in another group, over time.
Link to article
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