There’s a testosterone crisis in America—at least according to a number of Trump administration officials. Health and Human Services Secretary Robert F. Kennedy Jr., for example, has bemoaned the low-T of the American youth, and even boosts his own levels with testosterone replacement therapy. He’s also a major proponent of eating animals, celebrating the prominent position of meat and dairy in the new food pyramid the US Department of Agriculture unveiled at the beginning of this year.
But a study published last month in the International Journal of Food Sciences and Nutrition suggests Kennedy might be able to ease up on the testosterone shots if he ate more vegetables.
A team of nutritional and metabolic scientists analyzed the four-day dietary intake and hormone levels of more than 2,500 middle-aged men living in Finland. It’s worth noting that the data in their study were also middle-aged, collected during the Kuopio Ischaemic Heart Disease Risk Factor Study between 1984 and 1989.
Read more: “The Impossible Strength of the Testosterone Myth”
After dividing the men into four groups according to their protein intake and controlling for other variables, the researchers found that the subjects’ testosterone levels seemed to be linked to the kind of protein they preferred. On average, the men who ate more meat and dairy had slightly lower testosterone levels. In contrast, those who got more of their protein from plant-based sources had slightly higher levels of the sex hormone. The scientists observed a similar dynamic with their levels of sex hormone binding globulin, a protein that controls how much free testosterone is available in the blood stream.
Drilling down into the dietary data, the team discovered dairy was most responsible for the relatively low-T in the animal protein group. The plant protein group’s higher testosterone levels showed a closer association with protein from vegetables, rather than cereals.
The researchers said they aren’t entirely sure why the protein source appears to affect male sex hormone levels, but said the pattern may be mediated by inflammation. Higher levels of C-reactive protein, a molecule involved in inflammatory pathways, have been linked to reduced overall testosterone levels and those who eat more plant protein typically have lower levels of C-reactive protein.
Additionally, while the researchers controlled for a number of health and lifestyle variables, it’s possible that the plant-eating group had healthier habits overall. But because this is a cross-sectional observational study, causation is impossible to pin down.
Of course, there are plenty of other reasons to limit meat intake—both for your own health and the planet’s. In fact, a new international food pyramid released this week recommends getting the bulk of your calories from plants instead of animals. Testosterone-maxxing might just be an attractive bonus.
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