Can dietary changes help treat disease?

Good nutrition is key to good health, but new studies are needed to identify appropriate diets for different diseases

We know that a diet high in ultra-processed foods containing excess sugar and salt is bad for health and can lead to chronic diseases and cancer. We also know that good nutrition helps people recover from illness, and for some health issues, it can be as effective as drug treatment.

To date, dietary interventions have demonstrated the most direct benefits when treating cardiovascular disease and type 2 diabetes. As explained by an article published in the journal Nature, many studies have shown the direct relationship between what we eat and these two forms of chronic disease.

In one study, American researchers demonstrated that the DASH diet (Dietary Approaches to Stop Hypertension)—which incorporates fruits, vegetables, whole grains, and low-fat dairy, while eliminating salt, saturated fats, and alcohol—significantly reduces blood pressure compared to other interventions, such as the Mediterranean diet, which allows for moderate amounts of red wine and salt.

The reduction was similar to results observed in studies of pharmacological therapies, such as the medicine nitrendipine, suggesting that the DASH diet could be an alternative to drugs for people with early-stage hypertension.

In another study, it was found that a Mediterranean diet (supplemented with extra-virgin olive oil or oilseeds) reduced major cardiovascular events to a greater extent than a low-fat diet in adults at high risk for this type of disease.

The research showed that the intervention reduced rates of heart attack, stroke, and even death.

Diabetes remission

Dietary changes can also benefit people with diabetes. In the Diabetes Remission Clinical Trial (DiRECT), more than 300 participants with type 2 diabetes stopped taking all medication and began a total diet replacement that restricted their calorie intake.

Significantly more patients on the new diet achieved diabetes remission within 12 months than among those receiving care in line with current best practices.

The team that ran the study, led by Naveed Sattar at the School of Cardiovascular and Metabolic Health in Glasgow, UK, also found that more than a third of the participants assigned to the dietary intervention remained in remission for 24 months.

“Type 2 diabetes has the most evidence for being modified by dietary interventions, since weight loss can rapidly improve glucose levels,” Sattar told Nature.

The findings had a direct impact on public policy in the country: the UK’s National Health Service (NHS) has started recommending low-calorie diets to patients with type 2 diabetes.

“It is clear that further studies are needed to identify the impact of diets that cause significant weight loss on many other diseases,” adds Sattar, who is also president of the British government’s Obesity Mission.

Gaps

Despite the promise of the “food as medicine,” there are many gaps in the evidence, especially for illnesses other than heart disease and type 2 diabetes.

We know, for example, that dietary interventions can be effective against endocrine disorders and other conditions that primarily affect women, such as polycystic ovary syndrome and endometriosis.

A healthy diet can also reduce the risk of osteoporosis and bone fractures in women during menopause and old age. Obesity often co-occurs with polycystic ovary syndrome.

One study found an association between adherence to a Mediterranean diet and reduced severity of the disease. Diet and exercise are recommended to women with the problem, but the ideal diet for tackling the syndrome is not yet known.

This is also true for cases of dementia, often associated with hypertension, type 2 diabetes, and obesity. If it were possible to treat these three chronic problems with dietary changes, then dementia would also be indirectly addressed.

The article also mentions the possibility of studies finding personalized diets for specific cases, especially when a person is known to have a certain gene that can lead to specific diseases and syndromes, such as Alzheimer’s.

Research challenges

Scientists have long noted that there are a range of problems involving studies on diet. From a classic lack of funding to the challenge of making sure a person sticks to a certain diet through to the end of the study.

Another oft-cited obstacle is the lack of underrepresented groups in trials of dietary interventions.

In the DiRECT study, for example, most participants were white, although the risk of type 2 diabetes is higher in other ethnic groups, such as people of South Asian descent.

It is also difficult to carry out this type of study on a large scale, since many low- and middle-income countries still dedicate more resources to studies on malnutrition.

While the research continues, Sattar argues that only governments are capable of “changing the environment so that people can choose healthier foods without great awareness or effort.”

Such changes have been implemented in Singapore, which taxes sugary drinks and alcohol, but also subsidizes healthier foods, such as whole-grain products.

Food and nutrition insecurity is a worldwide problem and millions of people do not have access to healthy food—something experts agree is essential for managing disease, improving health, and reducing healthcare costs.

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