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Raw Foods Diets
REVIEW OF THE LITERATURE
by Suzanne Havala Hobbs, DrPH, RD
It is well established that vegetarian lifestyles are associated with health
advantages. The American Dietetic Association states that "
planned vegetarian diets are healthful, are nutritionally adequate, and provide health
benefits in the treatment and prevention of certain diseases." (16)
Much of what is known about vegetarian diets and related health effects is based on
research on lacto ovo vegetarian diets. Relatively little information is available about
the health and nutrition aspects of vegan diets, however, as well as variants such as raw
foods or living foods diets. A review of the literature was conducted to determine the
extent to which there is scientific documentation of the health and nutrition aspects of
raw foods diets as a first step toward further study of this dietary practice.
Worldwide, little research data is available on the subject of raw foods diets. The
majority of published research has been conducted in Finland at the University of Kuopio.
Of the 24 papers included in this review, 15 originated in Finland. The remainder of the
research was conducted in the U.S., the Netherlands, and Germany.
Raw foods diets are variously described as uncooked vegan diets, uncooked vegetable
diets, and "living foods" diets. In one case, a raw foods diet included raw
liver (8). All other studies reviewed here referred to vegetarian diets,
most of which excluded all animal products and derived the majority of calories from
uncooked plant matter. In one study, up to 95 percent of food was consumed in raw form (7). One study group derived 55 percent of calories from uncooked fruits,
carrot juice, salads and raw vegetables, and grain products, though 58 percent of subjects
also consumed some animal product during the recorded week of food intake (4).
In other studies, a "living foods" diet was defined as an uncooked vegan diet
that included germinated seeds, sprouts, cereals, vegetables, fruits, berries, and nuts (9, 11).
The scientific literature contains relatively little information about the rationale
for a raw foods or living foods diet. One paper by Kenton (1985) provides philosophical
discussion examining food energy and its role in sustaining optimal health. Other papers
focus on specific health effects on adult subjects following a raw foods or living foods
diet for a period of time ranging from as little as one week (10) to as
long as 3.7 years (14). Study groups ranged in size from as small as 13
subjects (2) to as many as 513 subjects (14). Findings
include dietary effects on weight, serum lipid levels, symptoms of rheumatoid arthritis
and fibromyalgia, rates of dental erosion, fecal microflora, cancer treatment, vitamin B12
status, and antioxidant and other nutrient intakes.
Four studies found uncooked vegan ("living foods") diets to be associated
with substantial loss of weight (5, 12, 14,
20). In one case, weight loss was associated with reduction of diastolic
blood pressure (5), in one case reduction of fibromyalgia symptoms (12), and with amenorrhea in another case (14). Other
studies found subjective improvement of fibromyalgia and rheumatoid arthritis symptoms
with adoption of an uncooked vegan diet (9, 11, 17).
An uncooked vegan diet was associated with decreased serum total and LDL-cholesterol
levels (2). Another study found that long term uncooked vegan diets
resulted in decreased levels of n-3 fatty acids due to high intakes of linoleic and oleic
acids (1). Two studies found significant reductions of serum vitamin B12
concentrations in subjects following a raw foods ("living foods") diet,
suggesting that long-term adherents to a raw vegan diet should include a reliable source
of vitamin B12 in their diets (3, 22).
Other studies focused on favorable effects of an uncooked vegan diet on fecal
microflora and other potential chemopreventive factors for cancer risk (6,
15, 18, 25). One study found overall
favorable changes in biochemical and metabolic health indicators including serum protein,
urea, and total cholesterol in subjects eating a raw foods diet for one week but concluded
observation over a longer period was needed (10). One study found
increased risk of dental erosion in subjects following an uncooked vegan diet (7).
Another study examined coumarin 7-hydroxylation in subjects consuming a raw foods vegan
diet matched with omnivorous controls and concluded that plant substances had little
effect on coumarin hydroxylase activity in subjects consuming a raw foods diet (23).
Finally, one study of 141 American long-term (mean time 28 months) adherents to a raw
foods diet found self-reported improvements in health and quality of life after adoption
of the diet (4). Measurement was based on survey results of
subjects current health and retrospectively for health prior to dietary changes. The
study found that salads, fruits, carrot juice, and cooked grain products provided 60-88
percent of most of the nutrients found in the diet. Dehydrated barley grass juice, nuts
and seeds, potatoes and squash provided the remaining 12-40% of nutrients in the diet. The
diet provided a mean calorie intake of 1460 kcal/day for women and 1830 kcal/day for men.
Fat provided 24% of calories, and mean protein intake was 0.66g/kg body weight. Mean
calcium intakes were 580 mg/day for women and 690 mg/day for men. As compared to mean
nutrient intakes of people in the United States, as reported in the National Health and
Nutrition Examination Survey (NHANES III), intakes of several nutrients were significantly
higher in subjects eating a raw foods diet, and intakes of several nutrients were lower.
Intakes of fiber, vitamins A, B6, C, and E, folate, copper, and potassium were
significantly higher in subjects eating a raw foods diet as compared with those reported
in NHANES III, and intakes of protein, total and saturated fat, cholesterol, vitamin B12,
phosphorus, sodium, and zinc were significantly lower.
Overall, the body of scientific literature describing health and nutrition aspects of
raw foods or living foods diets is limited. Only one survey of American individuals
consuming a raw foods diet has been reported. Little or no information is available
describing the rationale for a raw foods diet, nor has the range of practices among
individuals consuming raw or living foods diets been documented. The majority of available
research findings related to raw foods diet is confined to studies of European
1. Agren, J. J., Tormala, M. L., Nenonen, M. T., Hanninen, O. (1995). Fatty acid
composition of erythrocyte, platelet, and serum lipids in strict vegans. Lipids, 30,
2. Agren, J. J., Tvrzicka, E., Nenonen, M. T., Helve, T., Hanninen, O. (2001).
Divergent changes in serum sterols during a strict uncooked vegan diet in patients with
rheumatoid arthritis. British Journal of Nutrition, 85, 137-139.
3. Donaldson, M. S. (2000). Metabolic vitamin B12 status on a mostly raw
vegan diet with follow-up using tablets, nutritional yeast, or probiotic supplements. Annals
of Nutrition & Metabolism, 44, 229-234.
4. Donaldson, M. S. (in press). Food and nutrient intake of Hallelujah vegetarians. Nutrition
& Food Science.
5. Douglass, J. M., Rasgon, I. M., Fleiss, P. M., Schmidt, R. D., Peters, S. N.,
Abelmann, E. A. (1985). Effects of a raw food diet on hypertension and obesity. Southern
Medical Journal, 78(7), 841-844.
6. Gaisbauer, M., Langosch, A. (1990). Raw food and immunity (article in German). Fortschr
Med, 108(17), 338-340.
7. Ganss, C., Schlechtriemen, M., Klimek, J. (1999). Dental erosions in subjects living
on a raw foods diet. Caries Research, 33, 74-80.
8. Gerson, M. (1978). The cure of advanced cancer by diet therapy: a summary of 30
years of clinical experimentation. Physiol Chem Phys, 10(5), 449-464.
9. Hanninen, O., Kaartinen, K., Rauma, A. L., Nenonen, M., Torronen, R., Hakkinen, A.
S., et al. (2000). Antioxidants in vegan diet and rheumatic disorders. Toxicology, 155,
10. Hanninen, O., Nenonen, M., Ling, W. H., Li, D. S., et al. (1992). Effects of eating
an uncooked vegetable diet for 1 week. Appetite, 19, 243-254.
11. Hanninen, O., Rauma, A. L., Kaartinen, K., Nenonen, M. (1999). Vegan diet in
physiological health promotion. Acta Physiologica Hungarica, 86, 171-180.
12. Kaartinen, K., Lammi, K., Hypen, M., Nenonen, M., Hanninen, O., Rauma, A. L.
(2000). Vegan diet alleviates fibromyalgia symptoms. Scandanavian Journal of
Rheumatology, 29, 308-313.
13. Kenton, L. (1985). Raw energy nutrition of the future? Nutrition and
Health, 4, 37-50.
14. Koebnick, C., Strassner, C., Hoffmann, I., Leitzmann, C. (1999). Consequences of a
long-term raw food diet on body weight and menstruation: results of a questionnaire
survey. Annals of Nutrition & Metabolism, 43(2), 69-79.
15. Ling, W. H., Hanninen, O. (1992). Shifting from a conventional diet to an uncooked
vegan diet reversibly alters fecal hydrolytic activities in humans. Journal of
Nutrition, 122, 924-930.
Messina, V. and Burke, K. (1997). Position of the American Dietetic Association:
Vegetarian diets. Journal of the American Dietetic Association, 97(11), 1317-1321.
16. Nenonen, M. T., Helve, T. A., Rauma, A. L., Hanninen, O. O. (1998). Uncooked,
lactobacilli-rich, vegan food and rheumatoid arthritis. British Journal of
Rheumatology, 37, 274-281.
17. Peltonen, R., Ling, W. H., Hanninen, O., Eerola, E. (1992). An uncooked vegan diet
shifts the profile of human fecal microflora: computerized analysis of direct stool sample
gas-liquid chromatography profiles of bacterial cellular fatty acids. Applied
Environmental Microbiology, 58, 3660-3666.
18. Peltonen, R., Nenonen, M., Helve, T., Hanninen, O., Toivanen, P., Eerola, E.
(1997). Faecal microbial flora and disease activity in rheumatoid arthritis during a vegan
diet. British Journal of Rheumatology, 36, 64-68.
19. Rauma, A. L., Nenonen, M., Helve, T., Hanninen, O. (1993). Effect of a strict vegan
diet on energy and nutrient intakes by Finnish rheumatoid patients. European Journal of
Clinical Nutrition, 47, 747-749.
20. Rauma, A. L., Torronen, R., Hanninen, O., Verhagen, H., Mykkanen, H. (1995).
Antioxidant status in long-term adherents to a strict uncooked vegan diet. American
Journal of Clinical Nutrition, 62, 1221-1227.
21. Rauma, A. L., Torronen, R., Hanninen, O., Mykkanen, H. (1995). Vitamin B-12 status
of long-term adherents of a strict uncooked vegan diet ("living food diet") is
compromised. Journal of Nutrition, 125, 2511-2315.
22. Rauma, A. L., Rautio, A., Pasanen, M., Pelkonen, O., Torronen, R., Mykkanen, H.
(1996). Coumarin 7-hydroxylation in long-term adherents of a strict, Uncooked vegan diet. European
Journal of Clinical Pharmacology, 50, 133-137.
23. Rauma, A. L., Mykkanen, H. (2000). Antioxidant status in vegetarians versus
omnivores. Nutrition, 16, 111-119.
24. Verhagen, H., Rauma, A. L., Torronen, R., de Vogel, N., Bruijntjes-Rosier, G. C.,
Drevo, M. A., et al. (1996). Effect of a vegan diet on biomarkers of females. Human
Experimental Toxicology, 15, 821-825.
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