Arctic Paleo Diet: Eskimo Use of Plant foods
Although Vihljalmur Stefannson portrayed the traditional Eskimo diet as strictly carnivorous, Weston Price reported that Eskimos “were able to provide their bodies with all the mineral and vitamin requirements from sea foods, stored greens and berries and plants from the sea" (page 72 of Nutrition and Physical Degeneration).
Why the conflict? Stefannson studied Eskimos of the far Northern parts of Canada, who did eat almost exclusively carnivorous diets, whereas Price apparently spent time with Alaskan Eskimos who use more plant foods.
I have gotten ahold of two old papers that discuss the use plant foods by native Eskimos: One written by A.E. Porsild, former Chief Botanist of the National Museum of Canada, entitled “Edible Plants of the Arctic,” for the Encyclopedia Arctica , a project guided by Vilhjalmur Stefansson; and the other by J.P.Anderson, entitled “Plants used by the Eskimos of the Northern Bering Sea and Arctic Regions of Alaska,” which appeared in the American Journal of Botany, Vol. 36, November 1939.
Porsild reports that Eskimo use of plant foods varied from place to place, with it supplying not more than 5 percent of the diet in the Bering Sea region, less in North Central Canada, and variable amounts among Greenland Eskimos, with more consumed in western than eastern Greenland. In Porsild’s words:
“Among the Eskimo--the most widely distributed race of arctic aborigines the dependence on vegetable food varies from group to group according to tradition and according to what plants are available in the area occupied by them; thus, to the most northerly tribes the use of vegetable food is purely incidental and largely limited to the partly fermented and pre-digested content of the rumen of caribou and muskoxen, whereas in the diet of the Eskimo of southwestern Greenland, Labrador, and western and southwestern Alaska, vegetable food constitutes a regular, if not very large, item.”
As for quantity of plant food in Eskimo diets, Porsild states:
"Thus Weyer (1932) estimated that in the diet of the Eskimo of the Bering. Sea region vegetable food constituted no more than 5 per cent; among the Central Canadian Eskimo Stefansson (1914) and Jenness (1928) noted that it was scarcely used at all; in Greenland the part played by vegetable food has always been unimportant, except from a dietary point of view."
Based on his own expeditions, he states:
“Twenty-five years ago, I found that only a small number of plants was used by the Eskimo of northwestern Alaska. Among the more important were the leaves of Saxifraga punctata, the leaves and flowering axes of marshfleabane (Senecio congestus) and coltsfoot (Petasites frigiqys), all of which were made into a form of “sauerkraut” mixed with blubber; the root tubers of Eskimo potato (Claytonia tuberosa) and those of the vetch (Hedysaruvzalpinum) were gathered in considerable quantities and used during the winter cooked as a vegetable with meat. Of the several kinds of berries used, cloudberry or baked-apple (Rubus Chamamorus) and crowberry (Empetrum) were the most favoured. Both were eaten fresh or preserved frozen in sealskin bags.”
Thus, the Northwestern Eskimos ate some leaves, flowers, tubers and berries. Regarding seaweeds, Porsild states:
“A number of edible species of seaweed or marine algae occur along rocky shores of the arctic seas and several are used regularly, if mostly in times of scarcity, by the Eskimo. In Greenland, several species, including Rhodymenia palmata and Laminaria spp. [kelps] are eaten raw, dipped in boiling water or with seal oil. Rodahl (1950) estimated that 50 per cent of the vitamin C intake of the east Greenland Eskimo is derived from marine algae.”
This indicates that Eskimos used kelp "regularly, if mostly in times of scarcity." So was scarcity regular for Eskimos? In regards to vitamin C, Porsild states:
“The recent investigations by Rodahl (1944) and others, of the vitamin content of arctic plants, have demonstrated too, that it is just those arctic plants that are eaten by preference by nearly all arctic tribes, that have the highest content of ascorbic acid as well as of thiamine [emphasis added], and that the methods of preparation and of storing of vegetable foods used by these people are perhaps the best possible in the circumstances for the preservation of vitamins.”
Anderson visited Eskimo villages of the Northern Bering Sea and Arctic Alaska during the summer of 1938. He states:
“The diet of the Eskimos is almost exclusively of animal origin. The total portion that is directly vegetable is very small. The food plants growing in the vicinity of the villages indicated that but little had been gathered.”
Anderson also found the Eskimos using leaves (greens), taproots, tubers, seeds, and berries (including blueberries). He also reports that they preserved plant foods for consumption out-of-season by either fermentation or storage in oil or fat. I may devote another post to some of Anderson’s interesting observations on Eskimo use of plant foods.
According to the online Encyclopedia of Food and Culture entry on Inuit food and culture (http://www.enotes.com/food-encyclopedia/inuit), the wild greens and berries “are much sought” by Inuit. Anderson reports:
“Among monocotyledons, products of three species are consumed. The enlarged farinaceous [starchy] bases of a sedge, Carex sp., are called mouse food from the custom of robbing the nest of field mice (Microtis), which gather them for winter food. In some places fish is placed in the mouse nests so that the mice may live through the winter and be able to store a new supply of the sedge the following year.”
Thus he seems to indicate that Eskimos would “sacrifice” fish to feed mice so that they (the Eskimos) could get some starchy tubers! If so I would agree that Eskimos "eagerly sought" what plant foods they could get. (In another post I may report on similar practices among the Chukchi, another Arctic population popularly but incorrectly viewed as strictly carnivorous.)
So it seems possible that Eskimos would have preferred a greater portion of plant foods in their diets, but found that their environment could hardly meet their desires without some encouragement (e.g. feeding fish to the tuber-collecting mice) or fetching partially digested grasses from the guts of caribou.
Therefore, for purposes of estimating nutrient intakes, a proper analogue of an Eskimo diet would have not more than five percent of calories from plants consisting primarily of some greens and berries, and little kelp. I have created one with five percent of calories from dandelion greens, blueberries, and kelp (all species consumed by Eskimos), along with 50g (less than 2 ounces) of walrus liver, sardines with edible bones, and venison substituted for caribou, which possibly presents the best case scenario for an Eskimo:
This diet supplies 74% of energy as fat, 22% as protein (9% less than some estimates of usual protein intake for a precontact Eskimo) and 4% carbohydrate;
An analysis of micronutrients reveals a major excess of vitamin A and significant deficiencies of vitamin C, magnesium, manganese, potassium, and thiamin:
This presents the micronutrient contents graphically:
Although the FitDay software does not analyze for boron content, I can say almost certainly this diet lacks adequate boron because of its very low content of vegetables and fruits. Thus, with regard to bone mineral loss, this diet has several potential contributing factors:
1. High vitamin A content relative to vitamin D status. With less than 50g of walrus liver, this diet supplies 51, 537 IU (4183 mcg) of vitamin A, more than 4 times recommended intakes. Current research suggests that chronic high vitamin A intakes coupled with low vitamin D status may increase the risk for bone loss. In Vitamin A antagonizes calcium response to vitamin D in man, Johansson and Melhus report results of experiments in which they found that "an intake of vitamin A corresponding to about one serving of liver antagonizes the rapid intestinal calcium response to physiological levels of vitamin D in man." Given that this diet supplies only 771 IU of vitamin D and Eskimos had limited or no sun exposure at least half of the year and poor solar ray angle in the summer, I think it highly likely that they had a very unfavorable ratio of vitamin A to vitamin D.
2. Deficiency of vitamin C necessary for bone matrix formation.
3. Deficiencies of boron, magnesium and manganese, discussed in the Part V of this series.
4. Deficiency of potassium. Plant foods generally have a much higher potassium content than animal foods. This Eskimo analogue diet supplies less than half of the recommended intake of potassium. In "The effects of high potassium consumption on bone mineral density in a prospective cohort study of elderly postmenopausal women" Zhu et al report finding that "Potassium intake shows positive association with bone density in elderly women, suggesting that increasing consumption of food rich in potassium may play a role in osteoporosis prevention."
Hence, it seems that even in the best case scenario, an Eskimo diet may have had chronic nutritional issues besides acid load that may have promoted their early onset and rapid progression of bone loss.
If you take away all the plant foods and the liver, you get this:
Which when analyzed has the following macronutrient profile:
This shows how it measures up in micronutrients:
Now it has all the same deficiencies as the best case scenario, plus only supplies 10% of the vitamin A requirement and only 61% of the vitamin E requirement. It seems Eskimos would have more likely had the regular intake of liver promoting excessive vitamin A levels. The other deficiencies would have a negative effect on bone health.
Relating to pH, it now seems likely that it will be impossible to separate the effect of pH of food from the nutritional content. Plant foods provide the best sources of the nutrients deficient in these Eskimo analogues, and also have alkaline residues. Therefore, I feel inclined to say that the accelerated bone loss of Eskimos occured due to an imbalance of vitamins A and D along with a lack of nutrients better supplied by plant foods than animal foods. Whether we can have any confidence that lack of base-forming organic acids also plays a role or not I will explore in a future post.
Looking at the best case scenario Eskimo diet above, I estimate its pH residue as follows (fat is neutral so we can ignore it):
280g sardines @ 13.5 mEq per 100g = +38
196g venison @ ~8 mEq per 100g = +16 (used beef, venison not in database)
50g liver @ ~14 mEq per 100g = +7 (used veal liver, walrus liver not in database)
148g blueberries @ ~ –6.5 mEq = –10 (used black currants, blueberries not in database)
105g dandelion greens @ ~ –2.0 = –2 (used chicory, dandelion not in database)
Net +49 mEq, acidic.
At this point, still wonder if nutrient deficiencies can alone account for the uniquely high occurence of type II bone remodeling in the Eskimos. More on that in an upcoming post.