Monthly Archives: November 2024

Wait?! cat feces can make you taller?

According to this paper possibly. Toxoplasma is in food, cat feces, and can be transmitted from mother to child.

Are Toxoplasma-infected subjects more attractive, symmetrical, or healthier than non-infected ones? Evidence from subjective and objective measurements

The informal title and text of the article suggests doubt in the validity of the claims so will have to judge carefully. there’s also possibly selection bias, perhaps taller individuals are more likely to get infected. Especially since the parasite is sexually transmitted. It’s also possible that people who are more likely to be infected with taxoplasma also do other things that are beneficial to height like perhaps having a more diverse microbiome.

“Parasites are among the main factors that negatively impact the health and reproductive success of organisms. However, if parasites diminish a host’s health and attractiveness to such an extent that finding a mate becomes almost impossible, the parasite would decrease its odds of reproducing and passing to the next generation. There is evidence that Toxoplasma gondii (T. gondii) manipulates phenotypic characteristics of its intermediate hosts to increase its spread.”<-A beneficial parasite would be amazing. According to Wikipedia, “Up to half of the world’s population is infected by T. gondii, but have no symptoms” There are potentially negative effects though. Since half the population has it, it’s likely very easy to get so it’s not really worth it to go out to go it even if it did have beneficial effects.

“previous research has shown that Toxoplasma-infected men are, in average, 3-cm taller”

Toxoplasma-infected men have higher testosterone levels than non-infected ones”

Toxoplasma-infected (n = 35) and non-infected subjects (n = 178) were compared”

“Some sexually transmitted parasites, such as T. gondii, may produce changes in the appearance and behavior of the human host, either as a by-product of the infection or as the result of the manipulation of the parasite to increase its spread to new hosts.”

HEre are the studies cited in terms of toxoplasma and height:

Body height, body mass index, waist-hip ratio, fluctuating asymmetry and second to fourth digit ratio in subjects with latent toxoplasmosis

“Toxoplasma-infected men to be taller and Toxoplasma-infected men and women to have lower 2D : 4D ratios previously reported to be associated with higher pre-natal testosterone levels. The 2D : 4D ratio negatively correlated with the level of specific anti-Toxoplasma antibodies in Toxoplasma-free subjects. “

Higher perceived dominance in Toxoplasma infected men–a new evidence for role of increased level of testosterone in toxoplasmosis-associated changes in human behavior

“Toxoplasma is parasite of cats that uses any warm-blooded animals as intermediate hosts. It is known to induce shifts in behavior, physiology and even morphology of its intermediate hosts, including humans. The lower second to fourth digit ratio (2D:4D ratio) in infected man and women, and higher height in infected man suggest that sex steroid hormones like testosterone could play a role in these shifts.”

There are multiple papers that suggest that toxoplasma infected men are taller but given that height plays such a great role in mating success it is very likely that the taller height lends you to activities that increase the likelihood of getting it. We would have to understand better exactly how toxoplasma can make an individual taller.

There are some some studies that suggest toxoplasma can impact bone which could mean that it could impact height.

Seroprevalence and Association of Toxoplasma gondii with Bone Health in a Cohort of Osteopenia and Osteoporosis Patients

“an improvement in osteopenia and osteoporosis was observed in Toxoplasma-infected patients”

” we found higher mean T scores and bone mineral density of the spine and femur in the individuals infected with Toxoplasma, suggesting a protective role of toxoplasmosis in subjects with osteoporosis and osteopenia”