Digesting the study that reports poor diet causes one in five deaths worldwide

An analysis published this week highlighted the need for improved diet across nations. We were told to increase our intake of certain foods but also ensure we don’t eat too many of the wrong foods. Consequently there’s been some provocative headlines such as the BBC’s “The diets cutting one in five lives short every year”, and strong statements such as these naturally catch the eye. We investigated the findings and the foods included in both the so-called healthy and unhealthy categories merit discussio, at the very least. Because Diabetes.co.uk is a staunch advocate of a low carb, real-food diet – based on an expanding nutritional evidence base – there are some assertions which need challenging, because while they may catch the eye, they shouldn’t necessarily be accepted at face value.

What the diet study says

The Global Burden of Disease Study 2017 has been published this week in The Lancet [1], a prestigious medical journal. The authors reviewed the health effects of dietary risks in 195 countries and revealed that 11 million worldwide deaths were attributable to dietary risk factors. This equates to one in five deaths around the world, making it a bigger killer than smoking.

The analysis used estimates of countries’ eating habits to conclude how often diet was shortening lives. Around 10 of the 11 million deaths were due to cardiovascular disease, while cancers and type 2 diabetes accounted for the rest.

The findings are alarming, there can be no doubt of that. But there can be doubt over the causes. The researchers report that the dangerous diets were those containing:

Too much salt – associated with three million deaths
Too few whole grains – associated with three million deaths
Too little fruit – two million deaths

Low levels of nuts, seeds, vegetables, omega-3 from seafood and fibre were also shown to negatively impact our diets.

One important thing to note is that this is an epidemiological study, and so, it cannot prove cause and effect, it can only look for associations between certain dietary factors and disease risk.

Digesting the findings

There are a few notable takeaways regarding the foods highlighted. Nuts and seeds have both been found to have strong health benefits in recent years, aiding weight loss and lowering heart disease risk [2] [3]. Fibre is also beneficial for the body because it helps nurture our gut bacteria and reduce glucose spikes in response to food, though high fibre foods do vary in the amount of digestible carbohydrate they contain.

Whole grains, however, have been shown to be less healthy than we thought in recent years. Referring to things like cereal, wheat, barley and rice, whole grains have a reputation as being useful for reducing heart disease risk, but a 2017 study observed no positive effects on blood cholesterol or blood pressure attributable to whole grain diets [4]. Yes, whole grains are rich in dietary fibre, but they are high in carbohydrate, and it is carbohydrate which has emerged as a primary risk factor for type 2 diabetes and other health complications. Moreover, whole grains are by no means the only source of dietary fibre; nuts and seeds are packed with it.

That leads us on to fruit. Some fruits are incredibly healthy for us. These include berries, avocado, cantaloupe and watermelon, which are all very low in sugar. Bananas, grapes and mangoes however are much higher in sugar. A single medium-sized banana contains 14g of sugar and can have a prominent impact on blood glucose levels. It is consistently high blood glucose levels than can eventually lead to insulin resistance, the hallmark of type 2 diabetes.

The study also found that low omega-3 from seafood was a risk factor. Omega-3 fatty acids are renowned for their health properties, and can be found in oily fish and fish oil. Meanwhile, the study claimed that a diet low in “omega-6 fatty acids from all sources, mainly liquid vegetable oils, including soybean oil, corn oil, and safflower oil” was also a risk factor. This is rather unlikely, as such industrial omega-6 oils have been found to be proinflammatory, which can actually worsen chronic disease [5].

Next, salt. Most of us over the last 15 or 20 years will have likely been told by a GP, nurse or dietitian that too much salt raises blood pressure and raises the risk of heart attacks and stroke. Recent findings have refuted this claim though [6].

The Department of Health recommends we eat no more than 6g of salt a day, which is equivalent to one teaspoon of salt across the day. But this does not mean that we should avoid salt. Japa, which imports and consumes very high amounts of salt, had the lowest rate of all diet-related deaths (which may also be attributable to the high intake of omega-3-rich seafood) in the study review. Later this year renowned GP Dr David Unwin will speak at the Public Health Collaboration on how salt has taken the blame for the impact that sugar has on the heart.

Limitations

One of the unfortunate aspects of the study, and the way it has been reported, is that it lumbers together food groups. By grouping whole grains, fruit and vegetables together, the inference is they possess the same qualities. But there are vast differences in their nutritional properties. Not all of the foods in these groups are born equal. They all have varying properties that could lower the risk of health problems, but also varying properties that could increase the risk.

Furthermore, the researchers’ dismissal of sugar was alarming.

Professor Christopher Murray, director of the Institute for Health Metrics and Evaluation at the University of Washingto, said in an interview with BBC that sugar was a “much smaller issue” compared to the researchers’ standout findings. But sugar has been significantly linked with heart disease and a host of other complications in recent years [7]. The government’s 2018 introduction of the sugar tax is designed to reduce sugary drink consumption linked to obesity and type 2 diabetes rates, conditions which both have strong links to heart disease if not urgently treated. The Global Burden of Disease Study found that too many fizzy drinks were still being drunk worldwide.

The European impact

Where is the UK in all of this? A total of 14% of UK deaths were related to diet. This figure was behind countries like France, Belgium and Denmark.

Success stories were observed in Mediterranean countries. France, Spain and Israel had some of the lowest numbers of diet-related deaths, and it’s not hard to see why. The Mediterranean diet is gaining popularity for its incredible health benefits, including improved brain health, weight loss, lower heart disease risk, treating sexual dysfunction and reduced type 2 diabetes risk.

Ultimately, the findings from the study can be interpreted in a few different ways. But we know that diet is a very personal thing, and studies tend to crossover regarding their recommendations. If, however, you want to learn more about food and its impact on the body, then why not visit our award-winning Low Carb Program? One in four users of the program put their type 2 diabetes into remission within one-year, and other benefits members experience include better mood, increased energy and better quality of life.