Dairy and Prostate Cancer: What the Large Studies Report

Short answer: Large studies have found a small association between eating more dairy and a higher rate of prostate cancer, but expert reviewers rate the evidence as limited. A 2015 meta-analysis of 32 cohort studies found 7% higher risk for every 400 grams of dairy a day [1]. The World Cancer Research Fund calls this evidence "limited but suggestive", and it's one reason it makes no recommendation for or against dairy [2][3].

Association isn't the same as cause. These are observational studies, and men who eat a lot of dairy may differ from other men in ways the researchers can't fully measure. Here's what the biggest studies actually reported.

ProstateFoods shares general information about food and research. It isn't medical advice, and nothing here is meant to diagnose, treat or prevent any disease. Talk with your doctor about your own risk and diet.

What did the large studies find?

Risk figures are relative, not absolute. A 7% higher relative risk is a small change on top of a man's baseline risk.

To put 400 grams in perspective, a cup of milk weighs roughly 240 grams, so 400 grams is a little more than 1½ cups. The Adventist study's high group, at 430 grams a day [4], was in the same range.

What do expert reviews say?

The World Cancer Research Fund and American Institute for Cancer Research run the Continuous Update Project, which reviews published research on diet and cancer. They rate the evidence that dairy products might increase the risk of prostate cancer as "limited but suggestive," below the general threshold they use for making a recommendation [2].

That puts dairy in an awkward spot. The same body found strong evidence that dairy lowers the risk of colorectal cancer, largely because of its calcium [3]. Faced with a likely benefit for one cancer and a possible harm for another, its panel chose to make no recommendation on dairy at all [2][3].

A 2021 systematic review focused on milk reached a similar place. It said the positive association between milk and prostate cancer is well documented in epidemiological studies, but that very few experimental studies exist, and that there are no formal clinical recommendations on dairy for men at risk of prostate cancer [6].

Does the type of dairy matter?

The studies don't agree, and the subgroups are small.

• Low-fat and skim milk. In the 2015 meta-analysis, low-fat milk was associated with 6% higher risk per 200 g a day [1]. In the Physicians' Health Study, skim and low-fat milk were linked with low-grade, early-stage and screen-detected cancers [5].
• Whole milk. The Physicians' Health Study found whole milk associated only with fatal prostate cancer, and with progression to fatal disease among men already diagnosed [5].
• Cheese. Linked with 9% higher risk per 50 g a day, about 1¾ ounces, in the meta-analysis [1].

Because these patterns point in different directions, the meta-analysis authors suggested that something in dairy other than fat or calcium could explain the association [1]. Nobody has shown what that is.

Is it the calcium?

Probably not on its own. The 2015 meta-analysis found that calcium from dairy was associated with higher risk, but calcium from non-dairy foods wasn't [1]. The Adventist study found the same: higher non-dairy calcium intake showed no clear effect [4].

One exception in the meta-analysis: calcium from supplements wasn't linked to total prostate cancer, but it was associated with fatal prostate cancer [1]. If you take a calcium supplement, that's worth raising with your doctor.

If you're weighing other foods, see our list of foods high in vitamin D and our guide to soy for men, which covers what the hormone studies show.

So should men cut back on dairy?

The research doesn't settle that. The WCRF chose not to make a dairy recommendation either way [2][3], and the 2021 review found no formal clinical recommendations on dairy for men at risk of prostate cancer [6]. Dairy also supplies protein, calcium and vitamin B12, which the WCRF notes are important nutrients [3].

These studies compared men who ate a lot of dairy with men who ate little, and the Adventist study found the risk rose most at relatively low intakes [4]. Men who drink a lot of milk every day may want to talk it through with a doctor, especially if they already have a prostate cancer diagnosis. Our guide to foods to eat for prostate health covers the foods with the most consistent research, and red meat and prostate cancer covers the other big food question men ask.

Sources

1. American Journal of Clinical Nutrition. Dairy products, calcium, and prostate cancer risk: a systematic review and meta-analysis of cohort studies (Aune et al., 2015)
2. World Cancer Research Fund. Regional variations: recommendation evidence (dairy products and calcium)
3. World Cancer Research Fund. Dairy and cancer
4. American Journal of Clinical Nutrition. Dairy foods, calcium intakes, and risk of incident prostate cancer in Adventist Health Study-2 (Orlich et al., 2022)
5. Journal of Nutrition. Whole milk intake is associated with prostate cancer-specific mortality among U.S. male physicians (Song et al., 2013)
6. World Journal of Men's Health. Milk Consumption and Prostate Cancer: A Systematic Review (Sargsyan and Dubasi, 2021)

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