We review a very unique study conducted in 1990 about acne and diet. Not only are their conclusions explosive, but Loren Cordain, one of the researchers in the study, also drew conclusions for the famous Paleo diet from this as well. Acne is generally considered almost universal in the West. Two non-western people were studied, native Kitavans and the indigenous hunter-gatherers of Paraguay and both groups have almost no cases of acne. What does this mean for our understanding of acne, and might we find some revolutionary treatment for acne?
Background and Importance: The dermatology community has been skeptical of the relationship between diet and acne for several decades. This is because clinical data haven’t substantiated the relationship. However, one challenge to this view is that at least anecdotally, most patients believe that diet and acne are strongly correlated – clinical substantiation be damned. Even among medical students, this is a very firmly held belief, and doctors know this.
Dubbed the Kitavan Study, the findings challenge the accepted wisdom in the dermatology community that diet and acne are unrelated. Studying two groups who live mostly outside the reach of “western civilization,” researchers find somewhat incredibly that these people have no acne, which sharply contrasts with the western world where acne is almost universal. This is interesting data and one that is hard to obtain. Most clinical trials by necessity are in the midst of civilization, but this creates a blind spot and a bias in the sample. In terms of possible implications of the study, if there is a clear and modifiable factor that accounts for this massive gap in acne rate, it may pave the way for an intervention that is unprecedented in scale and efficacy.
The Kitavan Study
In the developed world, acne is considered a near-universal phenomenon throughout adolescence.5 An interdisciplinary team of medical doctors, nutritionists, and anthropologists went to Papua New Guinea to observe the native Kitavan population and a hunter-gatherer tribe in Paraguay. Contrary to expectation, in both groups, acne is almost non-existent, a finding that contradicts our understanding of acne as an inevitable rite of passage in developed nations.
This study is atypical in many ways. By necessity, most dermatology studies are conducted in medical facilities or universities, and the subjects being studied live a “Western lifestyle.” This is for a good reason – repeatability of results and sound methodology is integral to good science. However, one aspect rarely considered is that this quest for uniformity in our studies can ironically bias us heavily towards a specific population and lifestyle, namely, people who live close to the city or have practical access to one. This is not a traditionally controlled dermatology study, and its scope extends into anthropology and nutrition as well. It’s important to keep in mind the inherent advantages and disadvantages of the study framework when assessing the conclusions.
- Acne: Of 1200 Kitavan subjects (300 subjects aged 15-25) and the Aché hunter-gatherers of Paraguay (115 subjects, with 15 subjects aged 15-25), no cases of acne were observed, which departs radically from statistics in the West where acne is near-universal. The study also points out that the few studies conducted on non-industrialized populations show lower rates of acne.6 At the time of the study in 1990, electricity, telephones, and motor vehicles were absent.
- Diet: Approximately 2000 Kitavan people native inhabitants live in village groups that range from 20 to 400 people. Western food was accessible at the time of the study, but their lifestyle was mostly traditional, relying on horticulture and fishing.
- Note: No papules, pustules, or open comedones were observed. No closed comedones were observed, but they may be undetected.
The Aché of Eastern Paraguay
The Aché people settled in small communities near their traditional foraging range and now follow a mixed hunting-gathering and farming economy. Many aspects of Aché socioecology have been studied over the past 20 years.
- Acne: Not a single case of active acne vulgaris (mild, moderate, or severe or grades 1 to 4) was observed in all 115 subjects over the 843-day study period by any of the seven examining physicians. One 18-year-old man appeared to have acne scars. Not a single papule, pustule, or open comedo was observed in the entire population. Although no closed comedones were reported, the study recognizes that it is possible that closed comedones could have been present and gone undetected.
- Diet: The Aché diet contains wild, foraged foods, locally cultivated foods, and Western foods obtained from external sources. Their diet consists of 69% cultigens, 17% wild game, 8% Western foods, 3% domestic meat, and 3% collected forest products. The cultigens consist mainly of sweet manioc, followed by peanuts, maize, and rice, whereas the Western goods are restricted to pasta, flour, sugar, yerba tea, and bread.7
- Note: As in the Kitava sample, skin infections and intramuscular abscesses were common and responded well to treatment with antibiotics such as erythromycin and tetracycline.
Study Conclusions:
- While hereditary factors and genetic factors certainly play a role in acne, this alone is unlikely to account for the overwhelming difference in acne rates.
- Both the Aché and Kitavan diets are composed of minimally processed plant and animal foods. They are virtually devoid of typical Western carbohydrates that yield high glycemic loads that may acutely or chronically elevate insulin levels.
- Dietary interventions using low glycemic load carbohydrates may have therapeutic potential in acne treatment because of the beneficial endocrine effects of these diets.
- These endocrine changes are consistent with those known to promote normal follicular cell proliferation and reduce sebum production.
- Low glycemic load diets may have therapeutic potential in reducing acne symptoms, even in an otherwise Western person living in a developed country.
Discussion:
Diet, once wholly dismissed as a possible factor in acne (at least in the medical community, less so with patient experience), is once again becoming a topic of discussion and study,8 and this particular study from 1990 may have been an important part of starting this trend. There are also questions concerning other factors – after all, these traditional natives have lifestyles that differ in many ways outside of diet and sleep, exercise, genetics (which is acknowledged in the study), pollution or lack of, and other unaccounted for factors. Simply put, it’s not only their genetics that is different; everything about their entire environment is different.
We also know that sweeping conclusions should be taken with a grain of salt, especially in data and nutrition, due to the complexity of comparing apples to apples.9 Logistically, these types of studies are challenging to reproduce, as is standard practice in university halls and labs. Simultaneously, these types of unique studies add value and help propel the scientific community forward by questioning hidden and inherent biases, such as inadvertently restricting patient samples to people who have access to these labs. While many questions remain, it reopens the subject of diet and acne once again and is also a valuable lesson in methodology and science.
1A popular fad diet premised around predominantly eating foods available during the paleolithic era, avoiding processed foods, dairy, grains, sugar, and alcohol, focusing primarily on vegetables and meat. There is a fair bit of criticism about the scientific validity and overinterpretation of limited data in the paleo diet. https://en.wikipedia.org/wiki/Paleolithic_diet
2It’s often labeled “a myth.” In practice, though, many dermatologists are more pragmatic; if they claim that certain diets seem to cause acne for them, it makes sense to avoid or reduce those triggers.
3https://www.hindawi.com/journals/isrn/2014/727981/
4The lives of westerners and the study criteria vary in so many ways, making this challenging.
5Most estimates have a 95%+ incidence of acne in Western populations. I suspect that most people’s anecdotal experiences also corroborate this.
6https://jamanetwork.com/journals/jamadermatology/fullarticle/479093
7https://jamanetwork.com/journals/jamadermatology/fullarticle/479093
8https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2836431/
9http://fivethirtyeight.com/features/you-cant-trust-what-you-read-about-nutrition/
