Evidence of food’s claimed preventive and curative properties is also clear in modern scholarship. There are hundreds of research papers revealing that better-quality diets – those high in vegetables, fruits and good-quality proteins – are linked to better physical and mental health, and longevity.
Equally, there’s evidence that unhealthy diets – those higher in processed meat, refined grains, sweets and ultra-processed snack foods – are associated with higher rates of depression, anxiety, obesity, Type 2 Diabetes, cardiovascular disease, stroke, some cancers, certain dental diseases and premature death.
Significantly, scholars note these links are independent of one another. That is, a lack of nutritious food poses health problems even when ‘junk food’ intake is low, and processed foods are problematic even in those who also eat vegetables, legumes and other nutrient-dense foods.
Dietary sources of vitamins and minerals in unprocessed nutrient-dense foods are delivered in a complex matrix of constituents that work like an orchestra to enhance their bioavailability.
But what of the claim that food has curative properties?
Advanced Accredited Practising Dietitian and author, Sue Radd says the Portfolio Diet, comprised of clinically relevant amounts of viscous fibre, soy protein, plant sterols, and nuts has been shown to lower cholesterol as well as a starting dose of a first-generation statin.
"Even if you've already had a heart attack, the Lyon Diet Heart Study, for example, showed that adopting a Mediterranean style diet could reduce the risk of having a second heart attack by up to 70 percent,” says Ms Radd who is panellist this evening at a Sydney Ideas Health Forum that will unravel the therapeutic qualities of food and nutrition.
On the subject of cardiovascular risk reduction, Ms Radd says the Mediterranean diet also works better than medication and the low fat-diet recommended by the American Heart Association.
"Plant-based diets are a no-brainer,” says Radd, who is completing a PhD on the benefits of the traditional Mediterranean diet. “In one hit, they tackle so many of the problems that underlie chronic conditions like inflammation, high blood pressure and high cholesterol.
Plant-based diets are a no-brainer. In one hit, they tackle so many of the problems that underlie chronic conditions like inflammation, high blood pressure and high cholesterol.
“Plant-based diets also make it easier to lose weight without having to obsess about counting kilojoules. This is because of their higher content of fibre and polyphenols which can positively influence the microbes living in our gut.
“When you feed these microbes certain fibres, for example, they produce short chain acids such as propionate – a substance that helps us to eat less and which slows the generation of new fat cells."
Radd says the DASH Diet (Dietary Approaches to Stop Hypertension) is another example of how a nutritious diet can work as well as a prescription drug.
“It includes around nine serves of vegetables and fruit daily, together with reduced amounts of lean animal protein foods, more wholegrains but less salt – it lowers blood pressure by boosting levels of potassium, magnesium and calcium but reducing sodium.”
Reducing meat intake has also been linked to reduced risk for developing oral cancer, although the issue remains unresolved.
The era of a one-size-fits-all approach to diet and health may also be coming to an end.
The New York Times this month reported that over the next three years, scholars from the University of California, San Francisco and Stanford University will assess whether supplying 1,000 patients with congestive heart failure or Type 2 diabetes healthier food and nutrition education changes hospital readmissions and referrals to long-term care, compared to 4,000 similar patients who don’t get supplied meals and education.
In an already completed study, researchers at University of California, San Francisco tracked patients with HIV and Type 2 diabetes who got healthy meals for six months to see if it affected their health.
They reported patients were less depressed, less likely to make trade-offs between food and health care, and more likely to stick with their medications.
Further, their care cost less: the price of feeding each participant for six months was US$1,184 per person, less than half the US$2,774 cost for one day as an inpatient at a California hospital, according to the study.
People on marginal incomes often have a hard time controlling chronic diseases, because they often eat cheap foods laden with sugar and salt in preference to costly fruits and vegetables.
Recent figures show that four percent of Australians, including 22 percent of Aboriginal and Torres Strait Islander people, experience food insecurity.
Also, families that are welfare‑dependent spend 40 percent of their disposable income to afford a nutritious diet, compared to 20 percent for an average Australian family.
Unsurprisingly, people on low incomes are at greater risk for many chronic diseases and often live in regions where fast food outlets are 2.5 times more accessible compared to affluent regions.
It’s not only people faced with food insecurity, or those on lower incomes, who face hurdles when it comes to eating well and staying well.
Cancer patients, for instance, often lose their appetite due to treatment side effects that can lead to malnutrition, which further lessens the body’s ability to fight disease.
“Inadequate dietary intake of specific vitamins and minerals nutrients has been associated with a number of chronic illnesses,” says Dr Joanna Harnett, who will also speak at tonight’s Health Forum.
“These include Type 2 diabetes, cardiovascular disease and asthma.
“This has prompted research that investigates the efficacy of specific nutrient supplements as part of a treatment/management strategy in conjunction with standard care, such as studies evaluating the role of vitamin D in some respiratory conditions.
“We know, for instance, that specific doses of the omega-3 fatty acids found in fish oils, and some plant-based sources, can be effective in managing some of the specific risk factors of cardiovascular disease,” says Dr Harnett. “However, we also know they are not the panacea for reducing the risk of cardiovascular disease.
“Supplements may also be appropriate for special populations, such as adequate folic acid in reducing the risk of neural tube defects in pregnant women.
“Dietary sources of vitamins and minerals found in unprocessed nutrient-dense foods are delivered in a complex matrix of constituents that work like an orchestra to enhance their bioavailability”, Dr Harnett notes. “Also, the role of many plant chemicals known as phytonutrients are still being discovered.”
“The era of a one-size-fits-all approach to diet and health may also be coming to an end,” says Associate Professor Michael Skilton from the University of Sydney’s Charles Perkins Centre.
“Evidence beginning to emerge that specific diets and dietary components may be of more or less benefit for specific groups of people.
“This personalized medicine approach to nutrition may revolutionize the way we tailor dietary advice, with an emphasis on the individual person, as opposed to the population.”