Could eating steak increase the risk of diabetes? Yes, according to American experts who analysed the diet of more than 200,000 adults over 36 years.
In the study, Harvard scientists found that people with high levels of heme iron, the iron found in red meat, were up to 26 percent more likely to develop type 2 diabetes.
However, the same was not seen with plant sources of iron, such as beans and spinach, the experts said.
They added that their findings suggest that reducing red meat consumption and adopting a plant-based diet could help reduce the risk of diabetes.
Experts also warned vegetarians and vegans taking heme iron supplements could be increasing their risk of developing type 2 diabetes.
In the study, scientists at the Harvard T.H. Chan School of Public Health in Boston found that people with high levels of heme iron, the iron found in red meat, were up to 26 percent more likely to develop type 2 diabetes.
Publish your findings in the journal Nature’s metabolismThe authors said their study added to previous work supporting a link between heme iron and type 2 diabetes.
Their findings are based on data from a long-term study of more than 200,000 nurses and health care professionals in the United States.
The scientists examined how much iron the participants consumed and in what form, whether it was heme iron, plant-based iron or supplements such as iron-boosting pills.
This information was then compared to the participants’ health information to see if they had type 2 diabetes, taking into account several other health and lifestyle factors.
People with the highest intake of heme iron were found to be 26 percent more likely to have type 2 diabetes than those in the lowest intake group.
A separate analysis also examined the blood composition of a subgroup of study participants.
The blood was examined for biomarkers, chemical signatures, linked to how the body processes iron, as well as those for diabetes.
The experts found that higher heme intake was associated with more signs of type 2 diabetes in the blood, as well as lower biomarkers linked to a lower risk of diabetes, supporting their analysis.
The authors said their study had implications for dietary guidelines and public health strategies to reduce diabetes in the population.
They also noted that the findings had implications for vegetarians and vegans who add heme iron to their diet and who might think they are immune to the negative health impact of red meat.
Heme iron is also sometimes added to fake burgers such as vegan ones to improve their “meaty” taste and appearance.
In 2021/22, nearly 4.3 million people had diabetes and a further 850,000 people have diabetes and don’t know it, which is worrying because untreated type 2 diabetes can lead to complications such as heart disease and stroke.
Professor Frank Hu, an expert in nutrition and epidemiology and author of the study, said: “This study underlines the importance of healthy dietary choices in preventing diabetes.”
She added: “Reducing heme iron intake, particularly from red meat, and adopting a more plant-based diet may be effective strategies to reduce diabetes risk.”
Red meat has been demonized for decades due to a large body of evidence suggesting that eating too much of it can increase the risk of heart disease, cancer and premature death.
Although it is a good source of protein, vitamins and minerals, including iron, zinc and B vitamins, it can be high in salt and saturated fat.
When it comes to diabetes risk, red meat was previously thought to contribute to the problem due to its saturated fat content and the salt content in some processed versions.
Eating too much saturated fat can increase the risk of obesity, which is itself a risk factor for diabetes, while some studies have linked excessive consumption of salt, which is found in high amounts in red meats such as bacon, to the risk of type 2 diabetes.
The latest study is part of a series of studies pointing to heme iron as another risk factor, a substance thought to interfere with the body’s production of insulin.
Insulin is the hormone our body produces to help control blood sugar levels. People with diabetes do not produce enough insulin naturally, which causes their blood sugar level to be too high.
However, the link between red meat and diabetes is observational, meaning it cannot be proven that it or its heme iron levels are the direct cause of type 2 diabetes or whether other factors are also involved.
The latest research was also conducted on a cohort made up of nearly 80 percent women, who were mostly white, meaning the findings may have limited implications for men and other ethnic groups.
Another limitation is that data on participants’ iron intake were self-reported, meaning they could be influenced by errors.
UK health officials recommend eating no more than 70g of red meat (such as beef, lamb or pork) or processed meat (such as ham, bacon and salami) a day.
Red meat is rich in iron, which is essential for the production of red blood cells.
Not consuming enough iron can increase the risk of anemia.
Experts in the latest study said their findings suggested that cutting back on red meat and adopting a plant-based diet could help reduce the risk of diabetes.
Fatigue, shortness of breath, palpitations, paler than normal skin and headaches are telltale signs of iron deficiency.
Although a vegan or vegetarian diet can be high in iron, the iron in plant-based foods is not absorbed by the body as well as the iron in meat, so eating the right foods is vital.
The British Dietetic Association recommends that vegans consume foods or drinks containing vitamin C with plant-based iron, which helps the body absorb this form of the mineral iron more easily.
Some examples of foods rich in vitamin C are oranges, both fresh and in juice, strawberries, peppers, Brussels sprouts and potatoes.
Men aged 19 and women over 50 need 8.7mg of iron a day, and women aged 19 to 49 need around 14.8mg a day, according to the NHS.
For comparison, minced meat contains approximately 5.8 mg per 160 g serving, and lentils contain 4.9 mg per 125 g serving.
According to the NHS, legumes, wholemeal bread, fortified breakfast cereals, green leafy vegetables, nuts and dried fruit are good sources of iron.
Approximately 5 million people in the UK are living with diabetes, of whom approximately 850,000 are unaware they have the condition.
A recent report from Diabetes UK suggests there has been a staggering 39 per cent rise in type 2 diabetes in people under 40, a trend that has been attributed to rising levels of obesity.