Type 2 diabetes: eating a diet rich in fruit and vegetables daily lowers risk, study shows



The more fruit and vegetables consumed, the lower the risk.
Anna Shkuratova/ Shutterstock

Nita Forouhi, University of Cambridge; Ju-Sheng Zheng, Westlake University, and Nick Wareham, University of Cambridge

Eating about five servings of fruit and vegetables a day is widely promoted as a key part of a healthy diet. This is because consuming fruit and vegetables is linked to lowering the risk of health problems such as coronary heart disease, stroke and some types of cancer.

But there’s still confusion about the role that fruit and vegetables have in preventing type 2 diabetes. Evidence from research has been inconsistent, partly because most studies have relied on participants remembering what they ate – which can be inaccurate. But our latest research found that people who regularly ate more fruit and vegetables in their diet had half the risk of developing type 2 diabetes compared to those who ate less.

Since research shows that type 2 diabetes can be prevented through a healthy diet, we wanted to know just how important eating fruit and vegetables is as part of that. We conducted the world’s largest study that measured blood levels of vitamins linked to fruit and vegetable consumption in a population. This method of using objective nutritional biomarkers – indicators of dietary intake, metabolism or nutritional status that are present in our blood – cuts out the errors and inaccuracies that affected previous studies. We also asked people to report what specific foods they ate to compare with the biomarker data.

We followed a group of 340,234 people from eight European countries. We specifically studied biomarkers in 10,000 people who developed type 2 diabetes during follow-up and compared them with 13,500 people who didn’t.

The biomarkers we measured were levels of vitamin C and six different carotenoids or plant pigments in the blood. These biomarkers tell us about the fruit and vegetables a person gets in their diet. We then calculated the total sum of these seven nutrient biomarkers as a composite score, then split scores into five categories ranging from lowest consumption to highest.

We found that the higher the biomarker score level, the lower the risk of future type 2 diabetes. People whose biomarker score was in the top 20% of the population had a 50% lower risk of developing type 2 diabetes compared to those with lower scores. We also found that eating around 66 grams of fruit and vegetables daily could potentially cut risk of type 2 diabetes by a quarter.

One to two portions daily cut risk by a quarter.
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Our findings build upon the results of a smaller study of 21,831 people living in England, 735 of whom developed type 2 diabetes. This study showed a strong link between higher blood vitamin C level and lower risk of diabetes. But the link was weaker when examining fruit and vegetable intake as reported by the participants. By repeating this work on a larger scale and in several countries, our results further strengthen evidence that these results are likely to be repeated in other populations, too.

Five a day

Since UK dietary guidelines consider each portion of fruit or vegetable to be 80 grams, our study shows eating even one portion per day could have health benefits. For instance, seven cherry tomatoes, two broccoli spears, or one banana would all roughly equal one portion.

Although “five a day” has been around for decades, fruit and vegetable consumption remains low. Only one in seven people over 15 eat at least five portions everyday – and one in three people don’t eat any daily. Encouragingly, our results show there are large potential benefits from making small changes to our diets.

Our research highlights that reduced risk isn’t just because of certain nutrients or vitamins. Rather, the benefits we observed are because of the combination of multiple beneficial components found in fruits and vegetables. Alongside vitamin C and carotenoids, other components including fibre, potassium and polyphenols, which have beneficial effects on weight, body inflammation, blood sugar levels, and keep gut bacteria healthy. And a diverse variety of fruit and vegetables has the greatest health benefits, as you consume more of these beneficial components.




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We also took into account how several factors – including age, gender, body mass index, education level, occupation, smoking, alcohol intake, physical activity and use of vitamin supplements – all affected the risk of type 2 diabetes. We found that the biomarker results linked to fruit and vegetables were independent of these other factors – so regardless of whether a person smoked or was physically active, eating a diet rich in more fruit and vegetables is relevant for lowering the risk of developing type 2 diabetes.

Our research doesn’t establish cause and effect, because we did not intervene with dietary change – rather we observed what happened over time to participants with different blood biomarker levels. But, by using these objective measures and a large sample size in different countries with varying diets, our confidence in these findings is increased. We still don’t yet know whether our findings would be different among different ethnic groups, which should be a focus of future research.

It’s well known that fruit and vegetables are an important part of maintaining good health throughout life, but we also know that in reality the majority of people do not eat enough of them. Our study shows that even just a small increase in the amount of fruits or vegetables you get in your diet can significantly reduce your risk of developing type 2 diabetes.The Conversation

Nita Forouhi, Programme Leader, MRC Epidemiology Unit, University of Cambridge; Ju-Sheng Zheng, Principal Investigator, Human Nutrition and Epidemiology, Westlake University, and Nick Wareham, Director of the MRC Epidemiology Unit, University of Cambridge

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

A disease that breeds disease: why is type 2 diabetes linked to increased risk of cancer and dementia?



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Rachel Climie, Baker Heart and Diabetes Institute and Jonathan Shaw, Baker Heart and Diabetes Institute

In Australia, more than 1.1 million people currently have type 2 diabetes.

A host of potential complications associated with the disease mean a 45-year-old diagnosed with type 2 diabetes will live on average six years less than someone without type 2 diabetes.

This week we published a report bringing together the latest evidence on the health consequences of type 2 diabetes.

Aside from demonstrating the complications we know well – like the link between diabetes and heart disease risk – our report highlights some newer evidence that suggests type 2 diabetes is associated with an increased risk of cancer and dementia.




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Common complications of type 2 diabetes

Type 2 diabetes, which typically develops after the age of 40, is usually due to a combination of the pancreas failing to produce enough of the hormone insulin, and the cells in the body failing to adequately respond to insulin.

Since insulin is the key regulator of blood glucose (sugar), this causes a rise in the blood sugar levels.

Risk factors for developing type 2 diabetes include being overweight, being physically inactive, having a poor diet, high blood pressure and family history of type 2 diabetes.

Being overweight is a risk factor for type 2 diabetes – but not all people with type 2 diabetes are overweight.
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People with type 2 diabetes are about twice as likely to develop heart disease than people without type 2 diabetes.

While heart attacks, due to blockages in the coronary arteries, are perhaps the better recognised form of heart disease, heart failure, where the heart muscle is unable to pump enough blood around the body, is becoming more common, especially in people with type 2 diabetes.

This is due to a number of factors, including better treatment and prevention of heart attacks, which has allowed more people to survive long enough to develop heart failure.

People with type 2 diabetes are up to eight times more likely to develop heart failure compared to those without diabetes.




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Meanwhile, diabetes is the most common cause of kidney failure and vision loss in working age adults, and accounts for more than 50% of foot and leg amputations.

But beyond these common and familiar complications of diabetes, there’s mounting evidence to suggest type 2 diabetes increases the risk of other diseases.

Emerging complications of type 2 diabetes

People with type 2 diabetes are approximately two times more likely to develop pancreatic, endometrial and liver cancer, have a 30% higher chance of getting bowel cancer and a 20% increased risk of breast cancer.

Increased cancer risk is of particular concern for the growing number of people under 40 living with type 2 diabetes. In Australia, this group saw a significant increase in deaths from cancer between 2000 and 2011.

Dementia, too, is a recently recognised complication of type 2 diabetes. A meta-analysis involving data from two million people showed people with type 2 diabetes have a 60% greater risk of developing dementia compared to those without diabetes.




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Why the increased risk?

It’s important to acknowledge the studies we looked at are observational and can’t tell us diabetes necessarily caused these conditions. But they do suggest having diabetes is associated with an increased risk.

The two leading theories for why cancer risk is increased in people with type 2 diabetes relate to glucose and insulin.

Many types of cancer cells use glucose as a key fuel, so the more glucose in the blood, potentially, the more rapidly cancer will grow.

Alternatively, insulin can promote the growth of cells. And since in the early stages of type 2 diabetes insulin levels are elevated, this might also promote the development of cancer.

It’s especially important people with diabetes take up cancer screening programs.
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There are several possible explanations for the link between diabetes and dementia. First, strokes are more common in people with type 2 diabetes, and both major and repeated mini-strokes can lead to dementia.

Second, diabetes affects the structure and function of the smallest blood vessels throughout the body (the capillaries), including in the brain. This may impair the delivery of nutrients to a person’s brain cells.

Third, high glucose levels and other metabolic disturbances associated with diabetes may, over time, directly affect the way certain types of brain cells function.

Room for improvement

Despite well-established recommendations for the management of type 2 diabetes, such as guidelines for medication use, healthy diet and regular physical activity, there remains a significant gap between the evidence and what happens in practice.

A study from the US showed only one in four patients with type 2 diabetes met all the recommended targets for healthy levels of glucose, cholesterol and blood pressure.

Australian data has shown having diabetes is associated with 14% increased likelihood of discontinuing cholesterol medication after one year.

In our report, we showed increasing the use of a range of effective medications would prevent many hundreds of people with diabetes developing heart disease, strokes and kidney failure each year.




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With the burden of diabetes complications in our community casting such a large shadow in terms of death rates, disability and impact on the health system, we need greater education and support for people with living diabetes, as well as health professionals treating the condition.

For people with type 2 diabetes, close monitoring for other diseases such as cancer through screening programs is particularly important.

And alongside managing their blood sugar levels, it’s essential Australians with type 2 diabetes are supported to keep risk factors for complications, such as blood pressure and cholesterol, at healthy levels.

A healthy diet and regular physical activity is a good place to start.The Conversation

Rachel Climie, Exercise Physiologist and Research Fellow, Baker Heart and Diabetes Institute and Jonathan Shaw, Deputy Director, Baker Heart and Diabetes Institute

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

Had gestational diabetes? Here are 5 things to help lower your future risk of type 2 diabetes



For women who have had gestational diabetes, maintaining a healthy diet can help lower the risk of developing type 2 diabetes later on.
From shutterstock.com

Clare Collins, University of Newcastle; Hannah Brown, University of Newcastle, and Megan Rollo, University of Newcastle

Gestational diabetes is a specific type of diabetes that occurs in pregnancy.

Once you’ve had gestational diabetes, your risk of having it again in your next pregnancy is higher. So too is your lifetime chance of developing type 2 diabetes and heart disease.

The good news is taking steps such as adopting a healthier diet and being more active will lower those risks, while improving health and well-being for you and your family.




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What is gestational diabetes?

Gestational diabetes affects about one in seven to eight pregnant women in Australia.
Women are screened for gestational diabetes at around 24 to 28 weeks gestation using a glucose tolerance test. Gestational diabetes is diagnosed when blood glucose levels, also called blood sugar levels, are higher than the normal range.

Screening is designed to ensure women with gestational diabetes receive treatment as early as possible to minimise health risks for both the mother and the baby. Risks include having a baby born weighing more than four kilograms, and the need to have a caesarean section. Management of gestational diabetes includes close monitoring of blood glucose levels, a healthy diet, and being physically active.

The risk of developing type 2 diabetes increases markedly in the first five years following gestational diabetes, with risk plateauing after ten years. Women who have had gestational diabetes have more than seven times the risk of developing type 2 diabetes in the future than women who haven’t had the condition.

Type 2 diabetes

If type 2 diabetes goes undiagnosed, the impact on your health can be high – especially if it’s not detected until complications arise.

Early signs and symptoms of type 2 diabetes include extreme thirst, frequent urination, blurred vision, frequent infections and feeling tired and lethargic.

Doing regular exercise can lessen the risk of developing type 2 diabetes.
From shutterstock.com

Long-term complications include an increased risk of heart disease and stroke, damage to nerves (especially those in the fingers and toes), damage to the small blood vessels in the kidneys, leading to kidney disease, and damage to blood vessels in the eyes, leading to diabetes-related eye disease (called diabetic retinopathy).

If you’ve ever been diagnosed with gestational diabetes, here are five things you can do to lower your risk of developing type 2 diabetes.

1. Monitor your diabetes risk

Although gestational diabetes is a well-known risk factor for type 2 diabetes, some women have not been informed of the increased risk. This means they may not be aware of the recommendations to help prevent type 2 diabetes.

All women diagnosed with gestational diabetes should have a 75g oral glucose tolerance test at 6–12 weeks after giving birth. This is to check how their body responds to a spike in blood sugar after they’ve had the baby, and to develop a better picture of their likelihood of developing type 2 diabetes.

From that point, women who have had gestational diabetes should continue to have regular testing to see whether type 2 diabetes has developed.

Talk to your GP about how to best monitor diabetes risk factors. Diabetes Australia recommends a blood glucose test every one to three years.

2. Aim to eat healthily

Dietary patterns that include vegetables and fruit, whole grains, fish and foods rich in fibre and monounsaturated fats are associated with a lower risk of developing type 2 diabetes.

In more than 4,400 women with prior gestational diabetes, those who had healthier eating patterns, assessed using diet quality scoring tools, had a 40-57% lower risk of developing type 2 diabetes compared with women with the lowest diet quality scores.




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Glycaemic index (GI) ranks carbohydrate-containing foods according to their effect on blood glucose levels. The lower the GI, the slower the rise in blood sugar levels after eating. Research suggests that a higher GI diet, and consuming lots of high GI foods (glycaemic load), is associated with a higher risk of developing type 2 diabetes, while a lower GI diet may lower the risk of type 2 diabetes.

Take our Healthy Eating Quiz to check how healthy your diet is and receive personal feedback and suggestions on how to boost your score.

3. Be as active as possible

Increasing your physical activity level can help lower your risk of developing type 2 diabetes.

Engaging in 150 minutes of moderate-intensity exercise per week, such as walking for 30 minutes on five days a week; or accumulating 75 minutes of vigorous-intensity physical activity a week by swimming, running, tennis, cycling, or aerobics, is associated with a 45% lower risk of developing type 2 diabetes after having had gestational diabetes. Importantly, both walking and jogging produced a similar lower risk of type 2 diabetes.

In contrast, prolonged time spent watching TV was associated with a higher risk of type 2 diabetes in women with a history of gestational diabetes.

Strength training is also important. A large study of 35,754 healthy women found those who engaged in any type strength training, such as pilates, resistance exercise or weights, had a 30% lower rate of developing type 2 diabetes compared to women who did not do any type of strength training.

Women who did both strength training and aerobic activity had an even lower risk of developing either type 2 diabetes or heart disease.

Breastfeeding has been shown to reduce the risk of type 2 diabetes, even in mums who haven’t had gestational diabetes.
From shutterstock.com

4. Breastfeed for as long as you can

Research shows breastfeeding for longer than three months reduces the risk of developing type 2 diabetes by about 46% in women who have had gestational diabetes. It is thought that breastfeeding leads to improved glucose and fat metabolism.

The Nurses Health Study followed more than 150,000 women over 16 years. It found that for every additional year of breastfeeding, the risk of developing type 2 diabetes was reduced by 14-15% – even in mothers who had not been diagnosed with gestational diabetes.

Organisations such as the Australian Breastfeeding Association and lactation consultants offer support to help all women, including those who have had gestational diabetes, to breastfeed their infants for as long as they choose.




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5. Keep an eye on your weight

Weight gain is a known risk factor for developing type 2 diabetes. In a study of 666 Hispanic women with previous gestational diabetes, a weight gain of 4.5kg during 2.2 years follow-up increased their risk of developing type 2 diabetes by 1.54 times.

Another study saw 1,695 women with previous gestational diabetes followed up between eight to 18 years after their diagnosis. This research found that for each 5kg of weight gained, the risk of developing type 2 diabetes increased by 27%.

Aiming to modify your eating habits and being as active as you can will help with weight management and lower the risk of developing type 2 diabetes. Within interventions that support people to adopt a healthy lifestyle, one review found every extra kilogram lost by participants was associated with 43% lower odds of developing type 2 diabetes.




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The Conversation


Clare Collins, Professor in Nutrition and Dietetics, University of Newcastle; Hannah Brown, PhD Candidate Nutrition and Dietetics, University of Newcastle, and Megan Rollo, Postdoctoral Research Fellow, Nutrition & Dietetics, University of Newcastle

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