How can your diet impact body odor?

Who can resist a perfectly cooked steak? Well, vegetarians likely wouldn't, and cows probably aren't fans either.

There are both pros and cons to including red meat in your diet, with an ongoing debate surrounding its consumption. Red meat is rich in iron and protein, vital nutrients essential for tissue and muscle fiber. However, a significant study involving 500,000 Americans revealed that those who consume the most red meat are more likely to die, particularly from cancer and heart disease, compared to those who eat the least [source: Brody].

For some, the study's findings may not be all that surprising; smaller, less detailed studies have shown similar results for decades. However, this hasn't stopped America's fondness for red meat, as consumption rates have doubled in the U.S. since the 1960s.

There's another study, however, that may make red meat lovers reconsider. In 2006, an anthropological study conducted by researchers in the Czech Republic revealed that meat eaters tend to have a stronger body odor than vegetarians.

The researchers gathered samples of natural body odors from male meat eaters and non-meat eaters over a two-week period. After collecting the used underarm pads, the researchers presented them to 30 women who smelled and rated the odor on each pad. The results showed that the odors of non-meat eaters were "judged as significantly more attractive, more pleasant and less intense" [source: Havlicek, et al].

Why is this the case? The old saying 'you are what you eat' seems reasonable, but the idea that what you smell like depends on your food choices is less intuitive. How can a particular type of food or diet influence your body odor? To answer this, we'll first explore the science behind sweating.

The Science of Sweating

There are two main types of sweat glands on your skin (a third type, the sebaceous gland, is structurally and functionally similar but produces sebum instead of sweat). They are part of your integumentary system, which also includes your hair, nails, and skin. Sweat glands are also part of the excretory system. The first sweat gland to develop is the eccrine gland, which is found throughout your skin but most abundantly on the palms of your hands, the soles of your feet, your underarms (axillae), and your forehead.

Eccrine sweat glands are activated when the hypothalamus detects that the body's internal temperature is rising. The sweat released, which is mostly water and salts, helps cool the body down. Since eccrine sweat consists mainly of water and salt, it doesn't produce a noticeable scent and is not responsible for natural body odor. That role belongs to the apocrine glands.

The apocrine glands don't develop until puberty, and since they are the glands that cause body odor, this is why children usually don't begin using deodorant or antiperspirant until they hit puberty.

Apocrine glands are most concentrated in the axillae, around the genitals and breasts, and near the belly button. These glands help excrete waste, primarily proteins and lipids (fats). While this type of sweat itself is odorless, the scent is produced when it interacts with the skin. Healthy human skin is home to native flora (microorganisms such as bacteria and fungi), which begin to consume the apocrine sweat after it's released onto the skin. As they digest the sweat, these microorganisms produce the familiar body odor as a metabolic byproduct.

We've already seen that consuming red meat can lead to unpleasant odors. But what other foods should you avoid if you'd like to keep your scent fresh and pleasant?

Is there a non-stinky diet?

There is some debate among natural lifestyle proponents regarding the cause of body odor. In these circles, it's believed that body odor comes from the impurities and toxins released through sweat, rather than from bacteria feeding on the sweat's secretions [source: Adams]. Some even point to ama (undigested food, a concept in ayurvedic tradition) as the source of body odor. According to ayurveda, ama enters the bloodstream, acting as a toxin in the body before being expelled through sweat glands [source: McIntyre]. Previous discussions covered the subject from the standpoint of mainstream medical science. However, research into the exact foods that cause the most intense body odor is limited.

While science doesn't have the answers here, conventional wisdom still holds some weight. If the skin's native flora feed on fats and proteins and produce smelly byproducts like androstenes (steroid compounds) and isovaleric acid, reducing foods rich in these nutrients should decrease body odor. This can be thought of as 'starving' the bacteria to reduce odor. This may explain why meat-eating participants in the Czech study had less pleasant body odors compared to vegetarians. It's worth noting, though, that the study only showed a correlation between meat consumption and body odor perception, not a causal relationship.

Other foods often suggested to avoid in order to reduce body odor include those with strong smells, such as curries, onions, and garlic. The theory is that the enzymes that produce these foods' pungent odors might not be fully digested and could be excreted through the pores, creating body odor. However, this idea hasn't been confirmed by scientific research.

Food can also influence body odor indirectly. Spicy foods tend to make people sweat from both the apocrine and eccrine glands. Increased sweating could lead to more body odor, so cutting down on spicy foods might help reduce body odor [source: Mayo Clinic].

In the end, if you follow Western medicine's advice, regular bathing along with the use of antiperspirants or deodorants is the most effective way to reduce body odor. If the problem persists, seeking advice from a physician might be a good next step.