Not getting enough sleep is a common affliction in the modern age. If you don’t always get as many hours of shut-eye as you’d like, perhaps you were concerned by news of a recent study that found people who sleep less than six hours a night are at higher risk of type 2 diabetes.

So what can we make of these findings? It turns out the relationship between sleep and diabetes is complex.

The study

Researchers analysed data from the UK Biobank, a large biomedical database which serves as a global resource for health and medical research. They looked at information from 247,867 adults, following their health outcomes for more than a decade.

The researchers wanted to understand the associations between sleep duration and type 2 diabetes, and whether a healthy diet reduced the effects of short sleep on diabetes risk.

As part of their involvement in the UK Biobank, participants had been asked roughly how much sleep they get in 24 hours. Seven to eight hours was the average and considered normal sleep. Short sleep duration was broken up into three categories: mild (six hours), moderate (five hours) and extreme (three to four hours). The researchers analysed sleep data alongside information about people’s diets.

Some 3.2% of participants were diagnosed with type 2 diabetes during the follow-up period. Although healthy eating habits were associated with a lower overall risk of diabetes, when people ate healthily but slept less than six hours a day, their risk of type 2 diabetes increased compared to people in the normal sleep category.

The researchers found sleep duration of five hours was linked with a 16% higher risk of developing type 2 diabetes, while the risk for people who slept three to four hours was 41% higher, compared to people who slept seven to eight hours.

One limitation is the study defined a healthy diet based on the number of servings of fruit, vegetables, red meat and fish a person consumed over a day or a week. In doing so, it didn’t consider how dietary patterns such as time-restricted eating or the Mediterranean diet may modify the risk of diabetes among those who slept less.

Also, information on participants’ sleep quantity and diet was only captured at recruitment and may have changed over the course of the study. The authors acknowledge these limitations.

Why might short sleep increase diabetes risk?

In people with type 2 diabetes, the body becomes resistant to the effects of a hormone called insulin, and slowly loses the capacity to produce enough of it in the pancreas. Insulin is important because it regulates glucose (sugar) in our blood that comes from the food we eat by helping move it to cells throughout the body.

We don’t know the precise reasons why people who sleep less may be at higher risk of type 2 diabetes. But previous research has shown sleep-deprived people often have increased inflammatory markers and free fatty acids in their blood, which impair insulin sensitivity, leading to insulin resistance. This means the body struggles to use insulin properly to regulate blood glucose levels, and therefore increases the risk of type 2 diabetes.

Further, people who don’t sleep enough, as well as people who sleep in irregular patterns (such as shift workers), experience disruptions to their body’s natural rhythm, known as the circadian rhythm.

This can interfere with the release of hormones like cortisol, glucagon and growth hormones. These hormones are released through the day to meet the body’s changing energy needs, and normally keep blood glucose levels nicely balanced. If they’re compromised, this may reduce the body’s ability to handle glucose as the day progresses.

These factors, and others, may contribute to the increased risk of type 2 diabetes seen among people sleeping less than six hours.

While this study primarily focused on people who sleep eight hours or less, it’s possible longer sleepers may also face an increased risk of type 2 diabetes.

Research has previously shown a U-shaped correlation between sleep duration and type 2 diabetes risk. A review of multiple studies found getting between seven to eight hours of sleep daily was associated with the lowest risk. When people got less than seven hours sleep, or more than eight hours, the risk began to increase.

The reason sleeping longer is associated with increased risk of type 2 diabetes may be linked to weight gain, which is also correlated with longer sleep. Likewise, people who don’t sleep enough are more likely to be overweight or obese.

Good sleep, healthy diet

Getting enough sleep is an important part of a healthy lifestyle and may reduce the risk of type 2 diabetes.

Based on this study and other evidence, it seems that when it comes to diabetes risk, seven to eight hours of sleep may be the sweet spot. However, other factors could influence the relationship between sleep duration and diabetes risk, such as individual differences in sleep quality and lifestyle.

While this study’s findings question whether a healthy diet can mitigate the effects of a lack of sleep on diabetes risk, a wide range of evidence points to the benefits of healthy eating for overall health.

The authors of the study acknowledge it’s not always possible to get enough sleep, and suggest doing high-intensity interval exercise during the day may offset some of the potential effects of short sleep on diabetes risk.

In fact, exercise at any intensity can improve blood glucose levels.

Giuliana Murfet, Casual Academic, Faculty of Health, University of Technology Sydney and ShanShan Lin, Senior Lecturer, School of Public Health, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Rice is a culinary staple in Australia and around the world.

It might seem like a given that brown rice is healthier than white and official public health resources often recommend brown rice instead of white as a “healthy swap”.

But Australians definitely prefer white rice over brown. So, what’s the difference, and what do we need to know when choosing rice?

What makes rice white or brown?

Rice “grains” are technically seeds. A complete, whole rice seed is called a “paddy”, which has multiple parts:

1. the “hull” is the hard outer layer which protects the seed
2. the “bran”, which is a softer protective layer containing the seed coat
3. the “germ” or the embryo, which is the part of the seed that would develop into a new plant if was germinated
4. the “endosperm”, which makes up most of the seed and is essentially the store of nutrients that feeds the developing plant as a seed grows into a plant.

Rice needs to be processed for humans to eat it.

Along with cleaning and drying, the hard hulls are removed since we can’t digest them. This is how brown rice is made, with the other three parts of the rice remaining intact. This means brown rice is regarded as a “wholegrain”.

White rice, however, is a “refined” grain, as it is further polished to remove the bran and germ, leaving just the endosperm. This is a mechanical and not a chemical process.

What’s the difference, nutritionally?

Keeping the bran and the germ means brown rice has more magnesium, phosphorus, potassium B vitamins (niacin, folate, riboflavin and pyridoxine), iron, zinc and fibre.

The germ and the bran also contain more bioactives (compounds in foods that aren’t essential nutrients but have health benefits), like oryzanols and phenolic compounds which have antioxidant effects.

But that doesn’t mean white rice is just empty calories. It still contains vitamins, minerals and some fibre, and is low in fat and salt, and is naturally gluten-free.

White and brown rice actually have similar amounts of calories (or kilojoules) and total carbohydrates.

There are studies that show eating more white rice is linked to a higher risk of type 2 diabetes. But it is difficult to know if this is down to the rice itself, or other related factors such as socioeconomic variables or other dietary patterns.

What about the glycaemic index?

The higher fibre means brown rice has a lower glycaemic index (GI), meaning it raises blood sugar levels more slowly. But this is highly variable between different rices within the white and brown categories.

The GI system uses low (less than 55), medium (55–70) and high (above 70) categories. Brown rices fall into the low and medium categories. White rices fall in the medium and high.

There are specific low-GI types available for both white and brown types. You can also lower the GI of rice by heating and then cooling it. This process converts some of the “available carbohydrates” into “resistant starch”, which then functions like dietary fibre.

Are there any benefits to white rice?

The taste and textural qualities of white and brown rices differ. White rice tends to have a softer texture and more mild or neutral flavour. Brown rice has a chewier texture and nuttier flavour.

So, while you can technically substitute brown rice into most recipes, the experience will be different. Or other ingredients may need to be added or changed to create the desired texture.

Removing more of the outer layers may also reduce the levels of contaminants such as pesticides.

We don’t just eat rice

Comparing white and brown rice seems like an easy way to boost nutritional value. But just because one food (brown rice) is more nutrient-dense doesn’t make the other food (white rice) “bad”.

Ultimately, it’s not often that we eat just rice, so we don’t need the rice we choose to be the perfect one. Rice is typically the staple base of a more complex dish. So, it’s probably more important to think about what we eat with rice.

Adding vegetables and lean proteins to rice-based dishes can easily add the micronutrients, bioactives and fibre that white rice is comparatively lacking, and this can likely do more to contribute to diet quality than eating brown rice instead.

Emma Beckett, Adjunct Senior Lecturer, Nutrition, Dietetics & Food Innovation – School of Health Sciences, UNSW Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.