How do Inuit people not get scurvy?

In the past, a disease called scurvy caused many deaths due to vitamin C deficiency. Scurvy was associated with terrible suffering before leading to heart failure and death. The disease happened because of a lack of vitamin C in the diet, and it affected people in many parts of the world.

However, the Inuit people, who lived in the cold Arctic regions for thousands of years, seemed to avoid scurvy despite having a diet mainly based on meat from sea mammals. This puzzled scientists and explorers who wondered how the Inuit managed to stay healthy without fresh fruits and vegetables that are known to be rich in vitamin C.

The Inuit diet: Mostly meat

The Inuit people, also known as Eskimos, lived in places with long winters and limited access to fresh vegetables. Their diet primarily consisted of animal foods, especially meat from seals, fish, and other sea creatures. They occasionally ate some plants and berries when they were available during the warmer months.

The Høygaard Expedition

To understand the Inuit diet better, a group of scientists called the Høygaard expedition visited East-Greenland between 1936 and 1937. The study involved 21 Inuit males and 14 females who participated voluntarily. The researchers weighed and analyzed all the foods available in the households, both imported and traditional Inuit foods. They recorded any food gifts given or received by the families, as well as the quantities of blubber used for lamps, dog food, and stored food supplies. The researchers also collected data on the consumption of fresh, frozen, fermented, and dried animal foods.

Additionally, the scientists performed experiments to estimate the changes in food composition during cooking, as cooking can affect the vitamin C content in foods. They dissected various marine animals like seals, cod, guillemots, and ducks to analyze the meat, organs, and blubber for nutrient content, including vitamin C.

To calculate individual vitamin C intake, the researchers used an adult-equivalent conversion factor based on the household composition. The study period lasted for a total of 340 days, during which the researchers collected data on food consumption.

They studied the nutritional intake of the Inuit families living there. The goal was to find out how much vitamin C the Inuit were getting from their diet and what sources provided it.

Analyzing the data

The study involved analyzing the nutritional intake of Inuit individuals in East-Greenland to understand their sources of vitamin C. Researchers examined various foods consumed by the Inuit and calculated the amount of vitamin C present in each food item. Here is a tabular comparison of the vitamin C content of selected foods:

The highest amount of Vitamin C contains in Algae (Fucus serratus and Fucus vesiculosus)

Please note that the vitamin C content of foods can vary depending on factors like freshness, preparation methods, and species. Algae stands out as the richest source of vitamin C among the listed foods, providing significantly higher levels compared to other animal-based foods.

Cooking meat and organs led to a reduction in vitamin C content by approximately 50%. As a result, consuming raw or minimally cooked animal foods would be more beneficial in retaining the vitamin C content.

Additionally, the consumption of narwhal skin, eyes, and cod provided relatively low levels of vitamin C compared to other sources, making them less significant contributors to meeting vitamin C requirements.

On the other hand, the Inuit’s diet of raw and fresh seafood, particularly algae, plays a crucial role in meeting their vitamin C needs and preventing scurvy. Algae provided substantial amounts of vitamin C, making it a key component in their traditional dietary pattern.

The numbers 43 mg and 77 mg represent the quantity of vitamin C present in a given amount of these algae. This indicates that for every 100 grams (or another unit of measurement) of Fucus serratus, there is approximately 43 milligrams of vitamin C. Similarly, for every 100 grams of Fucus vesiculosus, there is even more vitamin C, around 77 milligrams.

Inuit adaptations to avoid scurvy

The Inuit are believed to have a unique genetic adaptation that could have allowed them to produce vitamin C internally. In most animals, including many mammals, the enzyme L-gulonolactone oxidase is responsible for the final step of vitamin C synthesis from simple sugars (monosaccharides) in the liver. However, humans lack this enzyme, which is why we need to obtain vitamin C from external sources like fruits and vegetables.

Vitamin C Synthesis Pathway: Plants and most animals create vitamin C from D-Glucose via enzyme L-Gluconolactone oxidase, while some mammals like humans lack this enzyme, resulting in no L-Ascorbic acid production

One theory suggests that the Inuit might possess a functional form of the L-gulonolactone oxidase enzyme, which could enable them to synthesize vitamin C internally. This adaptation could have evolved over time due to the Inuit’s traditional diet, which is predominantly composed of animal foods rich in nutrients.

If this theory is correct, it would mean that the Inuit have a unique advantage in environments where fresh fruits and vegetables are scarce. They would be less dependent on external sources of vitamin C, allowing them to avoid deficiencies and related health issues like scurvy.

The ability to internally produce vitamin C could have been a significant evolutionary advantage for the Inuit, particularly in their harsh Arctic environment. It would have ensured they have a steady supply of this essential nutrient even during the long winter months when plant-based foods are scarce or unavailable.

However, it is essential to note that this theory is still a subject of ongoing research and debate among scientists. More studies are needed to fully understand the genetic adaptations of the Inuit and their implications for vitamin C production.

Genetic protection against scurvy

Genetic protection against scurvy can be linked to a specific genetic trait known as haptoglobin. Haptoglobin is a protein in the blood that plays a role in binding and transporting hemoglobin, the molecule responsible for carrying oxygen in red blood cells. This protein also has antioxidant properties that help protect cells from damage caused by free radicals.

In some populations, there is a unique distribution of haptoglobin phenotypes that could provide a level of protection against scurvy. These phenotypes affect how efficiently haptoglobin functions in the body. Specifically, the haptoglobin-related gene may influence the body’s ability to conserve and recycle vitamin C, thereby reducing the risk of deficiency.

The Inuit population, known for their traditional diet heavily reliant on animal foods, particularly marine mammals, has been studied in this context. It’s been proposed that the prevalence of specific haptoglobin phenotypes in the Inuit could contribute to their resistance to scurvy.

Limitations of the study

The study had some limitations. For example, the researchers couldn’t track individual consumption accurately because they recorded food intake at the household level. Additionally, the Inuit’s diet relied on hunting, which made it difficult to control what people ate during the research.

Ancient observations and new insights

Historical accounts from early explorers also provided insights into the Inuit diet. Some reports mentioned that scurvy grass, a plant with high vitamin C content, was used as a remedy against scurvy in the past. Additionally, a case study of two Inuit individuals showed how algae played a crucial role in curing scurvy.

Conclusion

In conclusion, the study reanalyzing the Høygaard expedition’s data sheds light on the importance of algae consumption in the Inuit diet to prevent scurvy. It also challenges the belief that traditional foods like eyes from seals and narwhal skin were significant sources of vitamin C. Understanding the traditional Inuit diet helps us appreciate how different cultures adapt to their environments to meet their nutritional needs.

Further research is needed to fully grasp the role of genetics in protecting against scurvy and to understand the complex interactions between diet and health. Reanalyzing historical data in a modern and standardized way is essential to learn from traditional dietary patterns and gain valuable insights into human nutrition. By combining old knowledge with new scientific standards, we can unlock the mysteries of ancient diets and their impact on human health.

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