Men with prostate cancer may improve their odds of survival with one diet change, new research suggests. Replacing animal fats with plant-based options, such as olive oil and nuts, was linked to better survival.

The benefit appears closely tied to heart health. Other research also points to a possible slowing of the cancer itself.

Harvard T.H. Chan School of Public Health researchers tracked almost 5,000 men with nonmetastatic prostate cancer. Patients were followed for a median of 12.8 years.

The findings were published in JAMA Network Open on 2 September 2026. Prostate cancer affects around one in eight men during their lifetime.

It is the second most common cause of cancer death among US men. Only lung cancer claims more lives.

Around 333,000 new cases of prostate cancer are diagnosed in the US each year. Roughly one in 44 men will die from the disease.

Key Findings on Diet

More than 3,000 of the men died during follow-up. Around 400 deaths came from prostate cancer, while roughly 800 were linked to heart disease.

Higher saturated fat intake was tied to a greater risk of death overall. Replacing 5 per cent of carbohydrate calories with saturated fat raised that risk by 15 per cent.

The reverse swap brought benefits too. Replacing saturated fats with plant-based or monounsaturated fats was linked to a lower risk of death.

The results echoed an earlier Physicians' Health Study of almost 1,000 men. It found a 44 per cent lower risk of death from a similar fat swap.

Lorelei Mucci and independent experts discussed the findings with Newsweek. Mucci, one of the Harvard study's co-senior authors, said the benefits were likely down to several factors. Healthier fats can improve cholesterol and lower blood pressure, she explained.

Why Heart Health Matters

Dr Daniel Petrylak, of Yale University, said high-fat diets can raise inflammation markers. That inflammation may help prostate cancer grow, he said.

The study recorded twice as many heart disease deaths as prostate cancer deaths. Petrylak said this shows why heart health needs close attention too.

Many men live for years or decades after diagnosis, Dr Arul Chinnaiyan said. That makes cardiovascular health a key part of long-term survival.

A plant-based diet may protect the heart while supporting the whole patient, not just the cancer. Simple food swaps offer an easy starting point.

Using olive oil instead of butter is one example. Choosing nuts, seeds or avocados over saturated fats is another.

Mucci said it is never too late to eat more plant-forward. Small, steady changes can still make a real difference.

Cancer-Specific Evidence

A UC San Francisco study looked at over 2,000 men with localised prostate cancer. A plant-based diet was linked to a 47 per cent lower risk of the cancer progressing.

The diet included fruit, vegetables, whole grains, nuts and vegetable oils. Just one or two extra healthy servings a day were linked to the benefit.

Other research offers a mixed but supportive picture. A separate study found that men eating nuts five times a week had 34 per cent lower overall death rates.

It found no link to prostate cancer deaths specifically. It pointed instead to a wider health benefit.

An earlier JAMA Internal Medicine study of 4,577 men found similar results. High vegetable fat intake was linked to lower death risk from prostate cancer and other causes.

Doctors are careful not to overstate the case. Healthier fats cannot guarantee slower cancer growth or longer survival on their own.

But the evidence points to real gains for overall health. For men managing the disease, small daily diet changes may still bring lasting benefits.

Frequently Asked Questions

  • How can diet affect prostate cancer survival?
    Replacing animal fats with plant-based options can improve heart health and potentially slow cancer progression, thereby improving survival odds.
  • What are some examples of plant-based fats?
    Examples include olive oil, nuts, seeds, and avocados.
  • Why is heart health important for prostate cancer patients?
    Heart health is crucial because many prostate cancer patients live for years after diagnosis, and cardiovascular health is key to long-term survival.
Read more