Duane Mellor, Aston University
Ice cream lovers worldwide were probably rejoicing when a recent article suggested that indulging in your favourite flavour might be healthy. The article drew upon a 2018 doctoral thesis, which suggested that people with type 2 diabetes who consumed more ice cream had lower risks of heart disease. But as exciting as this sounds for those of us who sometimes enjoy indulging in a bowl of raspberry ripple, when we actually examine the study, it’s likely this link comes down to variety of other factors.
The 2018 research the article drew upon looked at data from the Nurses’ Health Study I and the Health Professionals Follow-Up Study. These were two large observational studies conducted by researchers at Harvard University which began in 1976 and 1986 and went on for around 20 years. The purpose of these studies was to track the health of participants over a long period of time, and uncover whether there were links between certain diseases and lifestyle factors (such as diet).
To conduct their analysis, the researchers only included data from participants of these two studies who reported having type 2 diabetes when the studies began – so around 16,000 people total. The participants with diabetes had also provided information about which foods they typically ate over the previous year. They were not instructed to eat or avoid ice cream at any point.
The researchers found that those who ate ice cream no more than twice a week appeared to be 12% less likely to develop cardiovascular disease, compared to those who didn’t eat ice cream.
But it’s important to note that this link between ice cream and heart disease only became apparent when other aspects of a person’s health, including how healthily they ate, were taken into account. This suggests that eating an overall healthy diet is perhaps more important in reducing cardiovascular disease risk in people with type 2 diabetes, than eating ice cream.
It could also be the case that participants who reported eating ice cream before joining the study could have stopped eating ice cream altogether just after joining the study – possible because they may have been made aware they were at greater risk of cardiovascular disease. This would then make it appear that eating ice cream was linked with lower risk of cardiovascular disease, when the reverse was true.
It’s also important to make clear that this was an observational study – meaning that it can only show an association between eating ice cream and lower risk of heart disease. It can’t actually prove eating ice cream in and of itself is directly responsible for decreasing risk of cardiovascular disease in people with type 2 diabetes.
To be able to test if ice cream has an effect on cardiovascular disease risk, it would probably need to go through a clinical trial, where one group ate ice cream as part of their diet and the other group ate a placebo for ice cream. This would be practically difficult to do, and given the potential costs is unlikely to ever happen without significant funding from the food industry.
Can ice cream be healthy?
Surprisingly, there have not been a lot of studies that have looked at the specific effect of ice cream on health. Studies that have done typically only had participants consume quite a small amount (around less than a quarter of a serving per day) – meaning it was not enough to develop any meaningful conclusions about its effect.
But one Italian study suggested that consuming more ice cream may be linked to a higher risk of non-alcoholic fatty liver (a risk factor for type 2 diabetes and heart disease). However, the researchers also found that this link existed for other foods, such as red meat – suggesting that the quality of a person’s overall diet may matter more for health than a specific food.
Ice cream is also considered an ultra-processed food – meaning that because of the processing methods used to create it, it’s typically very high in calories, fat and sugar. Ultra-processed foods have been linked to a range of health issues, including increased risk of developing both type 2 diabetes and cardiovascular disease. Nutrition guidelines also encourage us to limit our intake of sugar and fat because of this. This makes it pretty likely that too much ice cream may have a negative effect on health.
But it may not all be bad news if you’re someone who enjoys dairy products in general. Evidence for the potential benefits of dairy fat has been growing over the past 20 years, with research showing fermented dairy products – such as some types of yoghurt – and cheese in particular may reduce risk of heart disease and type 2 diabetes. However, more research will be needed to see whether ice cream may be associated with similar benefits because of it’s dairy fat content.
Research also shows that diets containing calcium-rich foods are associated with a decreased risk of type 2 diabetes and heart disease. But there are many other foods – including dairy, pulses and nuts – which are also sources of calcium. These also have other nutritional benefits without the negative high sugar content of ice cream.
While it can be exciting to see headlines claiming our favourite foods may have unexpected health benefits, it’s important to analyse the research. Often, the effects of one food can be exaggerated by research method errors or other factors – such as the participant’s diet or lifestyle.
At the moment, we simply don’t have enough good quality evidence to suggest that ice cream definitely has any health benefits. But a couple of small portions a week – paired with an otherwise healthy diet and exercise regime – is unlikely to do much harm.
Duane Mellor, Lead for Evidence-Based Medicine and Nutrition, Aston Medical School, Aston University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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