Episode Overview

Podcast: Stuff You Missed in History Class
Hosts: Tracy V. Wilson and Holly Frey
Episode: Rickets (Jan 26, 2026)

In this episode, Tracy and Holly delve into the historical understanding of rickets, a disease caused by vitamin D deficiency. The conversation explores how rickets was identified, named, depicted, and misunderstood before its connection to vitamin D and sunlight was made clear. The hosts bring together archaeology, medical history, and social context to illustrate how both scientific advancement and changing societies shaped our knowledge and treatment of rickets.

Key Discussion Points and Insights

1. Introduction to Nutritional Deficiencies and Rickets

[02:52] Tracy: The hosts introduce the theme, highlighting that rickets, like scurvy and pellagra, was treated effectively before its actual cause (vitamin D deficiency) was understood.

• Early treatments for deficiency diseases predated modern biochemistry.
• “People figured out two ways to treat [rickets] before we even knew what vitamin D was.” [03:40] Tracy

2. The Etymology and Naming of Rickets

[04:23] Holly, [05:03] Tracy:

• The origin of the word “rickets” is unclear.
• Possibilities: It might derive from a surname, from the word "rucket" (to breathe with difficulty), or from German/Swedish words meaning twisting/swaying.
• The disease was also known as “rachitis” (Latin/Greek), describing spinal inflammation.

3. What is Rickets? The Biological Basis

[05:46] Holly, [06:24] Tracy, [06:51] Holly:

• Rickets affects bone growth in children and young animals due to lack of vitamin D, which impairs calcium absorption and bone mineralization.
• Vitamin D comes from two main sources:
  • Diet (egg yolks, certain fish, wild mushrooms)
  • Sunlight (UVB converts cholesterol in the skin to vitamin D)
• “In the body, Vitamin D is converted into a hormone that affects the way calcium is absorbed in the digestive system.” [05:46] Holly

4. Sunlight, Skin Color, and Vitamin D Synthesis

[07:46] Holly, [08:21] Tracy:

• UVB exposure varies by latitude and can be blocked by glass, clothing, fog, and air pollution.
• Skin melanin reduces vitamin D synthesis; people with more melanin (darker skin) need more sun exposure.

5. Historical Prevalence of Rickets and Changing Lifestyles

[08:21] Tracy, [09:24] Holly:

• Ancient populations (hunters, gatherers, farmers) spent more time outdoors, limiting rickets.
• In the far north, lower sunlight was offset by diets rich in vitamin D (e.g., from fish).
• Babies are especially vulnerable (breast milk is low in D, swaddling reduces sun exposure).

6. Archaeological and Early Written Evidence

[10:30] Holly, [11:17] Tracy, [12:01] Holly:

• Archaeological finds (e.g., 5,000-year-old Scottish skeleton, Roman-era bones) show signs of rickets.
• Possible earliest written description: Soranus of Ephesus (~1st–2nd century CE) described infant care practices likely aimed at preventing deformity (“bowed legs and spinal curvatures are two of the most recognizable symptoms of rickets.” [12:01] Holly)

7. Recognition and Documentation in Early Modern Europe

[16:53] Tracy, [17:37] Holly, [18:43] Holly:

• Rickets becomes widely recognized in the 16th–17th centuries (artwork, medical records).
• Descriptions of children with bow legs or “richetic rosary” (knobs on the ribs) appear in medical accounts.
• Special waters (e.g., St. Willibrord's well) were used to try to treat these ailments.

8. The Naming and Recording of Rickets

[19:17] Tracy, [19:47] Holly:

• The first written use of “rickets” appears in a Yorkshire family’s medical receipt book (1632).
• The London Bill of Mortality (1634) lists rickets as a cause of death, indicating growing awareness.

9. Early Medical Theories and Social Implications [22:49–25:29]

• Daniel Whistler’s 1645 thesis: Detailed clinical description, identifies symptoms and speculates about causes (blood clots in viscera, class associations).
• Francis Glisson’s 1650 treatise: So influential, rickets is called “Glisson’s disease” or "English Disease" in parts of Europe.
• Early physicians thought rickets was new and especially common in England, possibly due to environmental changes (Little Ice Age, smog, poor nutrition).

Notable Quote:
“Glisson’s work was so influential that some people started calling rickets Glisson’s disease.” [25:08] Holly

10. Early (Ineffective) Treatments and the Move Toward Cod Liver Oil and Sunlight

[26:31] Holly, [26:58] Tracy, [27:53] Holly:

• Initial treatments followed humoral medicine, lacked efficacy.
• Cod liver oil emerged in the 18th century as an effective remedy—accidentally discovered as it was used for general malnutrition.
• Sunlight recommended by Polish physician Jedrez Sniadecki (1822) as preventive/cure ("the sun’s action on the body was one of the most efficient methods for the prevention and cure of rickets.” [28:32] Tracy).

11. Urbanization, Industrialization, and Public Health

[29:31] Holly, [30:21] Tracy:

• Industrial Revolution: Crowded cities, indoor labor, coal pollution -> rising rickets rates.
• Dietary changes (reduced fish, whiter flour with alum) may have made the problem worse.

12. Rickets in Animals and Institutional Research

[31:26] Holly:

• Rickets observed in zoo monkeys living behind glass (blocking UVB); many died of rickets rapidly.
  • “Nearly half of the monkeys in the gardens die rickety.” (John Bland Sutton, 1883)

13. Sunlight vs. Cod Liver Oil: Divergent Theories

[32:13] Tracy, [33:28] Holly:

• Into the early 20th century, some doctors argued for sunlight while others saw cod liver oil as the solution.
• Theobald Palm attributed low rickets rates in sunny Japan to “abundant sunshine” – missing the role of fish-rich diets.

14. Discovery of Vitamins and The Science of Rickets

[33:28] Holly, [34:50] Holly:

• 1912: Casimir Funk coins "vitamin," identifies rickets as a deficiency disease.
• Researchers hunt for the “anti-rachitic” (anti-rickets) factor, leading to confusion between vitamin A and D.
• Both cod liver oil and sunlight prove effective, but exact mechanism unclear for a time.

15. Landmark 20th-Century Studies

[34:50] Holly, [35:23] Tracy, [36:18] Holly:

• UV lamps found to cure rickets (even treating both arms when only one exposed).
• Cod liver oil shown to prevent rickets (not just treat it).
• Historical studies in NYC highlight higher risk among Black children due to less vitamin D synthesis at northern latitude.

Notable Moment:
“Today, this study would not be viewed as ethical, since other studies had already established that cod liver oil could be used to treat rickets.” [36:18] Holly

• Acknowledgment: Prevalence in Black communities was weaponized as racist pseudo-science (“This again was just about melanin and the sun.” [36:47] Tracy)

16. Isolation and Naming of Vitamin D

[37:06] Holly, [37:40] Tracy:

• Researchers distinguish vitamin D as separate from A; Elmer McCollum names it.
• 1921–22: Harriet Chick’s Vienna study shows both cod liver oil and sunlight prevent and cure rickets in infants—acceptance that both are valid.

Notable Quote:
“This study helped establish that rickets could be treated with both cod liver oil and sunlight. This was not the one or the other situation that a lot of researchers had been thinking that it was.” [39:30] Tracy

17. Decline and Modern Concerns

[40:04] Holly, [40:23] Tracy:

• Widespread use of cod liver oil, vitamin D supplementation, and fortification led to a sharp decline in rickets.

• Rickets persists for those with absorption disorders (celiac, IBD, cystic fibrosis), or with little sun exposure.

• Modern debate: Does sunscreen use contribute to rickets? Probably not as much as lack of outdoor time.

Notable Quotes & Memorable Moments

• “People figured out two ways to treat [rickets] before we even knew what vitamin D was.”
  — Tracy V. Wilson [03:40]
• “Bowed legs and spinal curvatures are two of the most recognizable symptoms of rickets.”
  — Holly Fry [12:01]
• “Glisson’s work was so influential that some people started calling rickets Glisson’s disease.”
  — Holly Fry [25:08]
• “Nearly half of the monkeys in the gardens die rickety.”
  — John Bland Sutton (quoted by Holly Fry) [31:30]
• “The sun’s action on the body was one of the most efficient methods for the prevention and cure of rickets.”
  — Jedrez Sniadecki (translated by Tracy) [28:32]
• “This study helped establish that rickets could be treated with both cod liver oil and sunlight. This was not the one or the other situation that a lot of researchers had been thinking that it was.”
  — Tracy V. Wilson [39:30]

Timestamps for Important Segments

• [02:52] — Topic introduction: nutritional deficiencies and early treatments.
• [05:03] — Etymology and history of the word “rickets.”
• [05:46]–[06:51] — Biological explanation of rickets: causes and sources of vitamin D.
• [08:21] — Discussion on early human populations, skin color, and sun/vitamin D.
• [10:30] — Archaeological and Roman-era evidence.
• [16:53] — Rickets in the Renaissance: early modern Europe and art.
• [19:17] — First written English use of “rickets.”
• [22:49]–[25:29] — Medical treatises and theories of causation.
• [26:58] — Emergence of cod liver oil as a remedy.
• [28:32] — Early advocacy for sunlight as a treatment.
• [31:26] — Victorian zoos and rickets in animals.
• [33:28] — Discovery of vitamins and the anti-rachitic factor.
• [34:50]–[39:30] — Key 20th-century studies and discovery of vitamin D.
• [40:04] — Modern persistence of rickets and concerns about sun exposure.

Overall Tone and Style

The conversation is consistently enthusiastic, inquisitive, and respectful of the science and social context of rickets. Both hosts use humor and conversational asides to make the dense historical content engaging and relatable. They are careful to acknowledge changing scientific understanding and the effects of social context (like racism and urbanization) on public health.

Conclusion

The episode traces the fascinating evolution of our understanding and treatment of rickets, from ancient misattributions and ineffective remedies to the eventual recognition that both sunlight and specific foods could prevent and cure the disease. Along the way, Tracy and Holly explore how language, environment, nutrition, and social changes intersect to influence disease and medicine—reminding us how often solutions precede explanations in medical history.