Charles Darwin’s Mysterious Illness

In the year 1831, two very important events happened to 22 year-old biologist Charles Darwin.   The first was that he boarded the Beagle, a research vessel upon which he would embark on a five-year journey to Central and South America.   There he would collect mountains of data on hundreds of plant and animal species, which he would then use to develop his theory of evolution by natural selection – the cornerstone of modern biology.The second event was that – just before boarding the Beagle – he fell extremely ill.   Darwin kept his condition secret for fear of being removed from the passenger list.   But this early bout of illness was just the beginning in a series of ailments that would continually affect nearly every aspect Darwin’s life for the next 40 years.The list of symptoms that plagued Darwin for the majority of his adult life included everything from chronic fatigue, severe abdominal pain, nausea and vomiting, headaches, insomnia, mouth ulcers, boils, anxiety, heart palpitations, and depression (just to name a few).   In his many letters to friends and colleagues, he constantly mentioned the wretched state of his health.   In 1865, he wrote to noted naturalist and friend William Hooker, “I have been [for] five or six wretched days miserable from morning to night and unable to do anything.”   Just a year earlier he had told Hooker, “for five months I have done nothing but be sick.”   His illness often precluded him from many public lectures and events expected of eminent scientists of the time.   His wife, Emma, tried to care for Darwin, as did numerous physicians, but his poor health remained until his death in 1882.The importance of Charles Darwin as a father of modern biology, combined with the complex and intriguing nature of his chronic illness, have led to many hypotheses as to why he suffered as he did.   Everything from heart disease to arsenic poisoning to a variety of psychosomatic causes have been proposed since his death.   However, it is only within the last several years that these hypotheses have focused on the gastrointestinal symptoms that seemed to plague Darwin most consistently.   Unable to examine the man himself, scientists have pored over his medical records, letters, and personal diaries, in order to posthumously diagnose Darwin’s debilitating illness.The Case for Lactose IntoleranceDuring the mid-19th century, lactose intolerance had not yet been described in great detail.   Most gastrointestinal problems were written off as ‘indigestion’ or ‘dyspepsia’.   Indeed, the genetics of lactose intolerance would not be discovered until more than 70 years after Darwin’s death.People diagnosed as lactose intolerant often suffer severe lower abdominal cramping and diarrhea after consuming milk or other dairy products (including some cheeses and various kinds of cream). Because the majority of Darwin’s symptoms appear to be centered around the digestive tract, a group of researchers from Cardiff University proposed in 2005 that the best explanation for Darwin’s symptoms was lactose intolerance.It is far more common to find lactose intolerance among South and East Asian populations, though it is not unheard of to find it among Europeans, where it reaches levels of about 8%.   Researchers, digging through his written correspondence, have found many key passages that hint at Darwin being lactose intolerant. For example, in 1865, Darwin wrote to H.B. Jones, his physician, recounting that “on most days, three hours after luncheon or dinner I have a sharpish headache on one side, and with bad flatulence last to the next meal.”   He also wrote to his friend and colleague, William Hooker, “I have had a bad spell.   Vomiting everyday for eleven days, and some days after every meal.”An analysis of his Diary of Health indicates that foods such as sugar, bacon, butter, and any desserts seemed to intensify his symptoms.   Unfortunately Darwin had a sweet tooth, and the majority of his wife’s recipes involved heavy cream.   To make matters worse, when Darwin was feeling particularly ill he was often given warm milk as a nightcap, a typical remedy during the mid-19th century.   This may have exacerbated his abdominal pain and discomfort.In fact, the only treatment that appeared to work was something called “hydrotherapy” in which the patient bathed and drank copious amounts of cold water.   Milk was not allowed.   This, some argue, is additional evidence in support of lactose intolerance being the primary cause of Darwin’s symptoms.The Case for Crohn’s DiseaseHowever, while most agree that the majority of Darwin’s symptoms were gastrointestinal in nature, some remain unconvinced that the best explanation was that Darwin was lactose intolerant.   Instead, they point to a more serious disorder known as Crohn’s Disease.   This new diagnosis is garnering much support within the medical community, in that Crohn’s — even more so than lactose intolerance — accounts for the vast majority of Darwin’s incapacitating symptoms.Crohn’s disease is a chronic autoimmune disease of the digestive tract.   It is found in about 1-2% of people of European descent, and can affect an individual’s entire digestive system, from the mouth to the anus and everything in between.   Additional symptoms include skin rashes, arthritis, and inflammation of the eye.   It usually first presents itself in early adulthood as a severe gastrointestinal infection.   Individuals suffering from the disease often have a series of flare-ups and remissions throughout their lives.   Crohn’s disease is believed to be a largely genetic disorder, though not all genetic markers have been identified.Various factors can influence the timing and frequency of flare-ups for sufferers of Crohn’s, including stress, nutrition, and other health issues.   Indeed, Darwin often noted worsening symptoms during periods of high stress, especially when he had to give public appearances or lectures.Upon close examination of Darwin’s correspondence and diaries by scientists at the University of Chile, his most severe symptoms included abdominal pain and vomiting, but virtually no mention of diarrhea, which is the main symptom of lactose intolerant individuals.   In fact, Darwin had reported regular bowel movements for the majority of his adult life.   It was the abdominal pain, nausea, and vomiting that plagued him for so many years, and these symptoms are key when diagnosing Crohn’s Disease.In addition, and perhaps more importantly, Darwin had several other health issues seemingly unrelated to the digestive tract, namely skin and eye irritation. Symptoms such as these are often found in patients diagnosed with Crohn’s Disease.   And the fact that there are conflicting reports on the kinds of foods that upset his illness (Darwin also reported getting sick after eating sugar, bacon, and salads), lends additional support that his illness was not related to a specific type of food (i.e. dairy).There is, of course, the possibility that Darwin suffered from both lactose intolerance AND Crohn’s Disease.   In fact, there is an 83% chance that individuals with Crohn’s Disease are also lactose intolerant.   However, the reverse is not also true, meaning the root cause of lactose intolerance among people with both conditions usually traces back to their Crohn’s.It also appears that there is some genetic aspect to Darwin’s illness, as many of his family members suffered chronic health problems.   In fact, the Darwin family was famous throughout the 19th and early 20th centuries as having overall poor health.   Darwin’s family history points to some kind of genetic disorder, and the symptoms of Crohn’s disease appear to be the most comprehensive explanation.The mystery surrounding Darwin’s chronic illness has mystified researchers for over 100 years.   If he were alive today, it is likely that physicians would have no trouble diagnosing what ailed him. And it’s too bad Darwin couldn’t sign up for 23andMe’s Personal Genome Service TM! Not only would the father of modern biology be fascinated by his genetic data, but it might have offered a clue to his lifelong illness as well by revealing whether he had a higher risk for lactose intolerance, Crohn’s Disease, or perhaps some other condition.
  • Jeff Monaghan

    Very interesting post. This begs the question, and I’m guessing I know the answer, but is there a process similar to 23andMe’s whereby someone’s genetic data can be uncovered posthumously? I realize it would be rather difficult extracting saliva from someone who has passed away, but are there other methods whereby genetic data can be uncovered?


  • steve t.

    I imagine that if he were lactose intolerant he would notice a loss of symptoms during the five year voyage on the Beagle – unless they took their own cows – or maybe they did!

    I can’t help finding it mildly ironic that one of the keenest observational minds in the history of science failed to take note of a family history of similar symptoms and draw the obvious conclusions – or maybe he did!

    Lucky for us that, despite not being the fittest, he survived.

  • Thanks for your comment, Jeff!

    Interestingly enough, there ARE ways to discover the genetics – to some extent – of deceased individuals without having to exhume their bodies! By obtaining DNA from several of Darwin’s direct descendants (great-grandchildren, etc.) we could examine their Health and Traits information to see their risk levels for both lactose intolerance and Crohn’s. However, due to the inheritance patterns for Crohn’s Disease (and, to a lesser extent, lactose intolerance) we may not find any conclusive evidence on Charles Darwin’s condition. But what an interesting research prospect for sure!

    Thanks for reading!


  • Hi Steve –

    Interestingly enough, that very issue was brought up a few years ago by physicians who were researching Darwin’s suspected lactose intolerance. As it turns out, sea voyages of the 19th century rarely had dairy products on board (due to the difficulties of preservation), so his dairy consumption would have decreased during the 5 year voyage. As a result, his symptoms would (theoretically) diminish as well.

    I also find it interesting that one of the fathers of modern biology and his physicians were unable to correctly diagnose him at the time! Just goes to show how the field of genetics has helped us to understand these disorders (and many more!).

    Thanks for reading!


  • gb14772

    Thanks for this post, it helped my wife diagnose mild lactose intolerance.

    Are there any genetic markers for lactose intolerance?

  • Hi gb14772!

    There are indeed genetic markers associated with lactose intolerance! One such gene is called the LCT gene. Normally, the LCT gene, which encodes lactase, is turned on only for the first few years of a mammal’s life. After this, the enzyme level decreases and with it the ability to digest large quantities of milk. But some people produce lactase throughout their life and can drink milk without uncomfortable side effects. In different populations across the globe, the local prevalence of the lactase persistent phenotype varies widely–between 0 and 100%. A genetic marker (or SNP) near the LCT gene controls whether the lactase enzyme is turned on or off as a person grows older.

    Fortunately, 23andMe customers can see whether or not their are likely to be lactose intolerant, as lactose intolerance is one of over 90 traits listed in our Health and Traits section.

    Thanks for reading!

  • Hollis

    Thankyou for this post, Darwin’s illness has puzzled me for so long and this sheds some light! I think that one of the possible reasons for darwin not being able to diagnose his own illness and link it to hereditory factors is because a part of him believed or feared that it was god’s punishment to him for doubting his word. At the time scientists believed that their job was to uncover god’s mysteries and it’s possible that darwin felt guilty for his ‘transmutationist’ theory which disproved genesis, that all god’s creatures were created at once, and in fact evovled over time. Therefore he did not look too closely at himself as it could have frightened him, this is alo a possible reason for him not going public with his ideas for so long, a personal turmoil between fact based theory and faith based belief.
    thanks again for the article,

  • Hollis

    ps illness on the beagle may have just been attributed to seasickness and foreign food! Anne have you also considered chagas disease? I believe the attributes of chagas would also fit his symptoms, what are your thoughts???

  • Hollis,

    I’m glad you enjoyed this article. I too find the sheer depth and breadth of Darwin’s illness(es) to be quite fascinating!

    It’s true that one of the alternative hypotheses for Darwin’s illness could be Chagas Disease; the thinking is that he contracted it whilst aboard the Beagle. However, there are many conflicting reports on this matter: Darwin did not report any of the typical initial symptoms, for example, and it is actually more difficult to get infected as it is not the insect bite which infects someone, but their excrement.

    There is a fascinating article in this month’s ‘American Scientist’ on the recent theories surrounding Darwin’s illness (including Chagas Disease), and I suggest you take a look if you haven’t already – you might find it interesting!


  • Glad I’ve finally found somtnehig I agree with!

  • With the desserts his wife made, perhaps it was gluten that was the problem? These symptoms sound a lot like gluten intolerance: Chronic fatigue, severe abdominal pain and flatulence, nausea and vomiting, headaches, insomnia, mouth ulcers, boils, anxiety, heart palpitations, and depression

    Fascinating reading! I really enjoyed this article and love this site! I look forward to getting my genes tested and sharing this info/testing with my anxious and depressed clients!

  • Deco

    Darwin’s symptoms are classic for somatoform disorders including hypochondriasis, obsessive compulsive disorder, anxiety and dysthymia. He probably had mini panic attacks from time to time. It is interesting that many people search in vain for some condition other than a mental health issue when the mental health issue is a plain as the nose on your face.

  • Washington Gail

    he obviously had come into contact with tropical intestinal parasites.