Does Hypothyroidism Explain Mona Lisa's Smile?

Liam Davenport

September 24, 2018

The unusual and enigmatic appearance of the Mona Lisa may be because she suffered from hypothyroidism, suggest two experts who cite not only the evidence visible in Leonardo da Vinci's famous portrait, but also her natural history and dietary patterns at the time.

In a letter published in the September issue of Mayo Clinic Proceedings, Mandeep R. Mehra, MD, from Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, and Hilary R. Campbell, BA, University of California, Santa Barbara, say the Mona Lisa may have developed the condition following a pregnancy.

In the painting, a portrait of Lisa Gherardini commissioned by her husband Francesco del Giocondo soon after the birth of their child Andrea in 1502, she shows numerous signs of hypothyroidism, even down to her famously inscrutable smile.

"We believe that the enigma of the Mona Lisa can be resolved by a simple medical diagnosis of a hypothyroidism-related illness that could have been the result of a peripartum thyroiditis accentuated by the living conditions of the Renaissance," Mehra and Campbell write.

"In many ways, it is the allure of the imperfections of disease that give this masterpiece its mysterious reality and charm," they add.

Did She Have Hyperlipidemia? More Likely, it Was Hypothyroidism

This is not the first time that the highly detailed yet mysterious portrait has been the subject of medical analysis.

In 2004, a team of rheumatologists and endocrinologists suggested that Gherardini had skin lesions on the left upper eyelid that were indicative of xanthelasma and the swelling on the upper dorsum of her right hand indicated a subcutaneous lipoma.

They therefore concluded that she may have suffered from familial hyperlipidemia and premature atherosclerosis, which could have caused her death.

Moreover, those authors posited that Gherardini's mysterious smile may have been the result of Bell's palsy.

However, in the current examination of the famous painting Mehra and Campbell say that, even if she had hyperlipidemia, it appears not to have been because of a familial or genetic cause as there are a lack of indicative factors.

Gherardini is also known to have lived to age 63 years. "It would have been unusual, if not impossible, to see her advance to that age in the presence of untreatable premature atherosclerosis from a genetically driven hyperlipidemia," they observe.

Instead, Mehra and Campbell suggest the "more unifying" diagnosis of clinical hypothyroidism.

They point to the yellowish color of Gherardini's skin, which can result from impaired hepatic conversion of carotene to vitamin A, and that her hair appears to be thinned.

"A complete lack of eyebrows or other hair throughout the pale skin further supports this diagnosis, and cascading hair down the side appears coarse in character," they add.

Mehra and Campbell also believe that, on closer inspection, Gherardini's neck "does insinuate the presence of a diffuse enlargement such as a goiter."

They point out that people with advanced hypothyroidism often have systematic metabolic dyslipidemia, which could explain the supposition in the 2004 article that she suffered from a form of lipid disorder.

"In this circumstance, if Lisa Gherardini was indeed suffering from severe hypothyroidism or its consequences, the mysterious smile may at one level be representative of some psychomotor retardation and muscle weakness leading to a less than fully blossomed smile," say Mehra and Campbell.

At the Time, Diet Was Poor and Iodine Deficiency Was Common

They add that dietary patterns in Renaissance Italy support the theory that she suffered from hypothyroidism, as people mostly ate a vegetarian diet of cereals, root vegetables, and legumes.

Furthermore, there were only 16 full harvests between 1375 and 1791, meaning that the diet in the region was often iodine deficient.

It is therefore not surprising, they note, that depictions of goiters are common in Italian Renaissance paintings and are the most prevalent condition in Byzantine artwork.

And given that Gherardini sat for the portrait shortly after giving birth, Mehra and Campbell suggest that she could, in fact, have been suffering from "a subclinical presentation of peripartum thyroiditis," leading eventually to hypothyroidism.

They do note, however, that the loss of facial and body hair "may be an intentional depilation," and the yellowish discoloration may be because of ageing of the pigments in the paint.

Finally, they suggest an alternative explanation: the enigmatic smile may have been Leonardo's invention, resulting from his experimentation with novel techniques.

Mehra has reported receiving consulting fees from Abbott, Medtronic, Janssen, Mesoblast, Portola, Bayer, and NuPulseCV. Campbell has reported no relevant financial relationships.

Mayo Clin Proc. 2018;93:1325-1331. Full text

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