Food as medicine: A different approach

The notion of food as medicine is certainly nothing new. You’ve probably heard the saying “Let food be thy medicine.” This is usually credited to the ancient Greek writer and physician Hippocrates. While this phrase does not actually appear in his written texts, he did believe that food and nutrition play key roles in health and medicine.

And now, 25 centuries later, the Food as Medicine movement is gaining steam as an organizing principle of medicine. While I think the movement is well-intentioned, I would like to push back on the idea that food is medicine. 

Pushing back on food as medicine

As I’m sure you’re aware, non-communicable diseases such as cancer, heart disease, Type 2 diabetes and obesity account for an enormous share of our society’s medical burden. These diseases are often referred to as “lifestyle diseases,” which is a term that I abhor. As if suffering from these diseases is just a matter of failing to make better choices, or a healthy lifestyle is equally available to everyone.

(As an aside, I’ve noticed that most proponents of “lifestyle medicine” tend to lead very comfortable lifestyles, in which a fridge full of healthy food, a kitchen to prepare it in, time to shop, cook, meditate, and go to the gym are all guaranteed. But I digress.)

Correlation between diet quality and disease risk

It is true that poor diet and nutrition are correlated with an increased risk of many of our most prevalent diseases. So the idea that a better diet could prevent or even treat these conditions is understandable.

But our current healthcare system is not oriented toward improving diet quality. Nor, for that matter, is it terribly focused on disease prevention. Most insurers will pay for drugs and hospitalizations but not salad bars. Which definitely seems short-sighted. Imagine how much more cost-effective (not to mention, humane) it would be to underwrite the costs of a healthy diet rather than the costs of drugs, surgeries, and medical devices!

But, for better or worse, we here in the U.S. endure a for-profit medical system. If we want to change the system, we’re going to need to show the receipts. Theoretically, if we could demonstrate that writing prescriptions for produce reduces the burden of disease, we might be able to convince insurers to ante up. 

Unfortunately, pilot produce prescription programs (say that 3 times fast!) have failed to bear fruit, as it were. Not that you’d know if from the press releases.

The question of produce prescription programs

Early in 2023, a study of 9 produce prescription programs was billed as “the largest evaluation of produce prescriptions and health outcomes to date, increasing statistical power to detect impacts on dietary intake, health outcomes, and other clinically relevant endpoints.”

Unfortunately, the impacts detected were of questionable validity. For one thing, there was no control group, so it’s impossible to attribute the improvements to the produce prescriptions, as opposed to other factors. And the improvements that were observed were only significant in certain subgroups of the population who had the worst values at baseline. 

Whenever you are measuring things in a large population, outliers will always tend to move toward the average over time. This effect is known as “regression to the mean” and could completely account for the modest improvements detected in this analysis.

How do you clean your produce? Bloggers recommend everything from bleach to baking soda. Food safety experts insist that tap water is all you need. What’s the best way to kill germs on fresh produce? Monica shares her take in the following episode; listen below.

A “Gold Standard” randomized trial and its surprising results

Just last month, a much better study was published. This was a randomized controlled trial (the “gold standard”). The study enrolled 500 patients suffering from Type 2 diabetes and randomized them into two groups. The control group were put on a waiting list. Meanwhile, the intervention group weren’t just given written prescriptions for fruits and vegetables. Participants were provided with ten healthy meals a week–enough for their entire family–for an entire year. 

If any study should have been able to document the impact of improved diet on diabetes management, it should have been this one. And people in the intervention group did show improved glycemic control at the end of the study. But so did the people in the control group. Much to the surprise of the researchers, there was no statistical difference between the groups that did and did not get the produce prescriptions.

Food as medicine & policy change

That’s not to say that the people receiving the healthy food did not benefit. Or that increasing access to (and demand for) healthy food is a bad idea. But if we are billing food as medicine, and hoping to get insurers to pay for it, we need to be able to demonstrate medical benefits.

I’ve written before about our tendency to over-inflate the impact of diet and nutrition on health and disease. Prudent diet and lifestyle choices can reduce our risk of disease. But not to zero. You can do everything “right” and still end up with Type 2 diabetes or cancer or heart disease. This is because there are so many other factors in play–including several that we don’t really have any control over, such as our age, sex, environment, genetics, and just plain luck of the biological draw.

To me, writing prescriptions for produce is a gimmick that confuses healthcare policy with food policy. In a nation as affluent as ours, we should absolutely be pursuing food policies that make healthy food more widely accessible. However, simply irrigating the so-called food deserts with produce stands is not sufficient.

Education and dietary diversity

We also need to educate people about both the benefits and the pleasures (as well as the practicalities) of nutritious diets. And all of this needs to be done in an atmosphere of respect and inclusion. The Mediterranean diet is not the only game in town. You can just as easily create a healthy diet with traditional foods from Africa, Asia, South America, Scandinavia, Eastern Europe or Indigenous cultures. 

If we could increase access to and appreciation for healthy food choices–across all strata of society, it might well reduce medical spending. But even if it didn’t, I still think it would be worth doing. Because food is not medicine. Food is food. And its purpose is not to reduce medical spending. Its purpose is to provide nourishment and enjoyment and to foster healthy bodies and communities.

Even if I could wave my magic wand and everyone was magically eating 5 servings of vegetables every day, people would continue to be diagnosed with Type 2 diabetes and heart disease and cancer. People would still need medical care. And our ability to diagnose, treat, and cure diseases is truly miraculous. 

Conclusion: food is food, medicine is medicine

Let’s not diminish the need for, or power of, actual medicine by conflating it with food and nutrition. And let’s not judge food solely according to its impact on disease risk. 

Food is food. Medicine is medicine. We need both.