Consumption of Black Beans and Navy Beans (Phaseolus vulgaris) Reduced Azoxymethane-Induced Colon Cancer in Rats.
Hangen L, Bennink MR.
Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824-1224.
Nutr Cancer 2002;44(1):60-5

Beans (Phaseolus vulgaris) are an important food staple in many traditional diets. There is limited evidence to suggest an inverse relationship between bean consumption and colon cancer. The objective of this study was to determine whether consumption of black beans and/or navy beans would reduce colon carcinogenesis in rats. Rats were fed a modified AIN-93G diet (control) or diets containing 75% black beans or 75% navy beans for 4 wk, and then colon cancer was initiated by administration of two injections of azoxymethane 1 wk apart. At 31 wk after the second injection, the incidence of colon adenocarcinomas was significantly lower (P < 0.05) in rats fed the black bean (9%) and navy bean (14%) diets than in rats fed the control diet (36%). Total tumor multiplicity was also significantly lower in rats fed the black bean (1.1) and navy bean (1.0) diets than in rats fed the control diet (2.2). The 44-75% reduction in colon carcinogenesis in rats fed beans was attributed to 1) more controlled appetites, leading to significantly less body fat, and 2) much greater concentrations of butyrate in the distal colon. It was concluded that eating black beans and navy beans significantly lowered colon cancer incidence and multiplicity.

The cholesterol-lowering effect of black beans (Phaseolus vulgaris, L.) without hulls in hypercholesterolemic rats.
Rosa CO, Costa NM, Leal PF, Oliveira TT.
Departamento de Nutricao e Saude, Universidade Federal de Vicosa, Brasil.
Arch Latinoam Nutr 1998 Dec;48(4):299-305

Caffeine is probably the most frequently ingested pharmacologically active substance in the world. It is found in common beverages (coffee, tea, soft drinks), in products containing cocoa or chocolate, and in medications. Because of its wide consumption at different levels by most segments of the population, the public and the scientific community have expressed interest in the potential for caffeine to produce adverse effects on human health. The possibility that caffeine ingestion adversely affects human health was investigated based on reviews of (primarily) published human studies obtained through a comprehensive literature search. Based on the data reviewed, it is concluded that for the healthy adult population, moderate daily caffeine intake at a dose level up to 400 mg day(-1) (equivalent to 6 mg kg(-1) body weight day(-1) in a 65-kg person) is not associated with adverse effects such as general toxicity, cardiovascular effects, effects on bone status and calcium balance (with consumption of adequate calcium), changes in adult behaviour, increased incidence of cancer and effects on male fertility. The data also show that reproductive-aged women and children are 'at risk' subgroups who may require specific advice on moderating their caffeine intake. Based on available evidence, it is suggested that reproductive-aged women should consume

Lipid accumulation in obese Zucker rats is reduced by inclusion of raw kidney bean (Phaseolus vulgaris) in the diet.
Pusztai A, Grant G, Buchan WC, Bardocz S, de Carvalho AF, Ewen SW.
Rowett Research Institute, Bucksburn, Aberdeen, UK. ajp@rri.sari.ac.uk
Br J Nutr 1998 Feb;79(2):213-21

The effects of inclusion of different levels of raw kidney bean (Phaseolus vulgaris) of high lectin content (27 g/kg meal) in a high-quality (lactalbumin) control diet were tested in nutritional trials on the growth and metabolism of obese Zucker (fafa) rats and their lean littermates in comparison with pair-fed controls. All diets contained 100 g total protein/kg and either 50 g lipids/kg (low fat) or 150 g lipids/kg (moderate fat). The growth of both obese and lean rats on bean diets was retarded by the daily bean intake in a dose-dependent manner. However, most of this was because bean-fed rats contained less body fat than the controls after 10 d. Thus, after feeding low-fat diets containing up to 130 g kidney bean/kg (lectin intake < or = 0.2 g/kg body weight (BW) per d) in both 10 d and 70 d trials, the bodies of obese rats contained less fat but not protein than their pair-fed controls. Moreover, by increasing the lipid content of the diet to 150 g/kg, the level of bean inclusion could be increased to 280 g/kg (lectin intake > or = 0.4 g/kg BW per d) without loss of body protein and skeletal muscle. Although these rats contained more body fat than those which were fed on low-fat diets, their weight reduction could be accounted for exclusively by reduced lipid content. In contrast, significant body protein loss occurred when the same diet of high lectin content was fed to lean littermates. Plasma insulin levels were significantly depressed in the obese Zucker rats on bean diets but the pancreas was not significantly enlarged nor its insulin content changed in 10 d trials. However, significant pancreatic growth occurred on long-term (70 d) bean feeding compared with pair-fed controls. The results suggest that, in addition to animal nutrition, it may also be possible to use the bean lectin as a dietary adjunct or therapeutic agent to stimulate gut function and ameliorate obesity if a safe and effective dose-range can be established for human subjects.

Antioxidant activity in common beans (Phaseolus vulgaris L.).
Cardador-Martinez A, Loarca-Pina G, Oomah BD.
Programa de Posgrado en Alimentos del Centro de la Republica (PROPAC), Research and Graduate Studies in Food Science, School of Chemistry, Universidad Autonoma de Queretaro, Queretaro, Qro., 76010 Mexico.
J Agric Food Chem 2002 Nov 20;50(24):6975-80

Beans were pearled to evaluate the feasibility of increasing antioxidant activity and phenolic antioxidants. Phenolics were concentrated mostly in the hull fraction at about 56 mg of catechin equivalents per gram of sample. The methanolic extracts of the pearled bean samples were screened for antioxidant potential using the beta-carotene-linoleate and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) in vitro model systems. The pearled material, also referred to as milled samples, exhibited antioxidant activity that correlated with phenolic content and inhibited DPPH significantly in a dose-dependent manner. Phenolics and antioxidant activities were also examined in chromatographic fractions of methanolic extracts of manually obtained hulls that represented a model used previously to ascertain antimutagenic activity. Fractions extracted with ethyl acetate/acetone and acetone displayed antioxidant activity, which implies potent free radical scavenging activity with antimutagenic activity.

Fat-free foods supplemented with soy stanol-lecithin powder reduce cholesterol absorption and LDL cholesterol.
Spilburg CA, Goldberg AC, McGill JB, Stenson WF, Racette SB, Bateman J, McPherson TB, Ostlund RE Jr.
Lifeline Technologies, Chesterfield, MO 63017, USA. Spilburg@aol.com
J Am Diet Assoc 2003 May;103(5):577-81

OBJECTIVE: The objective of this work was to show that fat-free, lecithin-formulated soy stanols lower cholesterol absorption and serum LDL cholesterol. DESIGN: Reduction in cholesterol absorption was measured in paired single-meal tests with or without formulated soy stanols (acute test), and changes in serum lipids were investigated in a 10-week, randomized, double-blind parallel trial in which formulated stanols or lecithin vehicle were given three times daily for the last 4 weeks (chronic test). SUBJECTS/SETTING: Forty-five normal or mildly hypercholesterolemic subjects were recruited for both studies. The 21 subjects (16 female, 5 male; mean age 32.5 years) in the absorption studies had the following mean lipid values: LDL cholesterol, 2.79 mmol/L and total cholesterol, 4.73 mmol/L. For the lipid reduction, 24 subjects (16 female, 8 male; mean age 50.6 years) were enrolled with mean LDL cholesterol and total cholesterol of 3.72 mmol/L and 5.66 mmol/L, respectively. INTERVENTION: Reduction in cholesterol absorption was measured using a lemonade beverage or egg whites that contained 625 mg stanols. Throughout the chronic study, subjects followed the American Heart Association Step I diet. During the 4-week treatment phase, subjects consumed daily a lemonade-flavored beverage containing either placebo or formulated soy stanols (1.9 g). MAIN OUTCOME MEASURES: Inhibition of cholesterol absorption was determined from the difference in plasma deuterated cholesterol enrichment after a test meal containing stanol-lecithin and one with lecithin vehicle only. In the chronic study, the primary endpoints were changes in LDL and total cholesterol. STATISTICAL ANALYSES PERFORMED: Paired or unpaired t tests were used to determine statistical significance. RESULTS: Stanol-lecithin reduced cholesterol absorption by 32.1% (P=.0045, n=10) and by 38.2% (P=.0022, n=11) when delivered in a lemonade-flavored beverage and in egg whites, respectively. Reduction in cholesterol absorption was strongly related to the initial level of absorbed cholesterol tracer in serum (r(s)=-0.739). Stanol-lecithin given in a beverage reduced total serum cholesterol by 10.1% (P=.0019, n=24) and LDL cholesterol by 14.3% (P=.0016, n=24). APPLICATIONS/CONCLUSIONS: Powdered soy stanol-lecithin lowers cholesterol absorption and LDL cholesterol when consumed in fat-free foods.

Soybeans, Soy Foods, Isoflavones and Risk of Colorectal Cancer: a Review of Experimental and Epidemiological Data.
Toyomura K, Kono S.
Department of Preventive Medicine, Faculty of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan kengot@phealth.med.kyushu-u.ac.jp
Asian Pac J Cancer Prev 2002;3(2):125-132

Incidence rates of colorectal cancer are relatively low in Asian populations, in which soy foods are commonly consumed. Soybeans and soy foods are an almost exclusive source of isoflavone intake. In in vitro studies, isoflavones have been shown to have various anticarcinogenic properties such as inhibition of protein tyrosine phosphorylation, induction of apoptosis, antiangiogenesis, and inhibition of DNA topoisomerase. Thus the protective role of soy foods and isoflavones in the etiology of colorectal cancer is a matter of interest. We therefore reviewed animal and epidemiological studies of colorectal cancer in relation to soybeans, soy foods, and isoflavones. Animal studies fairly consistently showed that soyfoods or isoflavones inhibited the formation of aberrant crypt foci, but did not clearly demonstrate an inhibitory effect of soy foods and isoflavones on the development of chemically-induced colorectal cancer. Several case-control studies have suggested that soy food consumption may confer a reduced risk of colorectal cancer although the findings are rather inconsistent. Most of the previous studies, especially in Japan, ascertained only the frequency of consuming selected soy foods, and thus were defective as regards the measurement of the total consumption of soy foods. Further epidemiological studies are needed to clarify the role for soy foods in colorectal carcinogenesis.

Soyfoods, soybean isoflavones, and bone health: a brief overview.
Messina M, Messina V.
Department of Nutrition, Loma Linda University, Loma Linda, CA, USA.
J Ren Nutr 2000 Apr;10(2):63-8

Soyfoods have received considerable attention during the past 5 years for their role in disease prevention, especially in relation to heart disease, osteoporosis, and cancer. However, limited research also suggests that soy protein favorably affects renal function. Much of the research interest in soy is aimed at establishing the physiological effects of isoflavones. Isoflavones are diphenolic compounds that have a very limited distribution in nature. Soybeans and soyfoods are, for practical purposes, the only nutritionally relevant dietary sources of isoflavones. Isoflavones are weak estrogens in that they bind to estrogen receptors, but they also have important nonhormonal properties as well. Initial speculation that soyfoods, and in particular isoflavones, might promote bone health was based on the estrogenic properties of isoflavones and the similarity in structure between isoflavones and the osteoporosis drug, ipriflavone, which is a synthetic isoflavone. In ovariectomized rodents, isoflavones retard bone loss almost as effectively as estrogen. Most research, but not all, also indicates that soyfoods rich in isoflavones favorably affect bone turnover and spinal bone mineral density in perimenopausal and postmenopausal women. However, studies conducted thus far have been of short duration and involved small numbers of subjects. Furthermore, no studies have actually examined the effect of soy feeding on fracture risk. Thus, although the data in general are encouraging, no firm conclusions can be drawn about the relationship between soy consumption and bone health. In addition to a possible direct effect of isoflavones on bone tissue, soy protein when substituted for animal protein may indirectly enhance bone strength. Several studies have found that in comparison with animal protein, soy protein decreases calcium excretion, a result of the lower sulfur amino acid content of soy protein. Although the high potassium content of soy is a consideration, the evidence clearly indicates that clinicians should consider recommending that their renal patients incorporate soyfoods into their diet.

Legumes and soybeans: overview of their nutritional profiles and health effects.
Messina MJ.
Nutrition Matters, Inc, Townsend, WA 98368, USA. markm@olympus.net
Am J Clin Nutr 1999 Sep;70(3 Suppl):439S-450S

Legumes play an important role in the traditional diets of many regions throughout the world. In contrast in Western countries beans tend to play only a minor dietary role despite the fact that they are low in fat and are excellent sources of protein, dietary fiber, and a variety of micronutrients and phytochemicals. Soybeans are unique among the legumes because they are a concentrated source of isoflavones. Isoflavones have weak estrogenic properties and the isoflavone genistein influences signal transduction. Soyfoods and isoflavones have received considerable attention for their potential role in preventing and treating cancer and osteoporosis. The low breast cancer mortality rates in Asian countries and the putative antiestrogenic effects of isoflavones have fueled speculation that soyfood intake reduces breast cancer risk. The available epidemiologic data are limited and only weakly supportive of this hypothesis, however, particularly for postmenopausal breast cancer. The data suggesting that soy or isoflavones may reduce the risk of prostate cancer are more encouraging. The weak estrogenic effects of isoflavones and the similarity in chemical structure between soybean isoflavones and the synthetic isoflavone ipriflavone, which was shown to increase bone mineral density in postmenopausal women, suggest that soy or isoflavones may reduce the risk of osteoporosis. Rodent studies tend to support this hypothesis, as do the limited preliminary data from humans. Given the nutrient profile and phytochemical contribution of beans, nutritionists should make a concerted effort to encourage the public to consume more beans in general and more soyfoods in particular.

Effect of green lentils on colonic function, nitrogen balance, and serum lipids in healthy human subjects.
Stephen AM, Dahl WJ, Sieber GM, van Blaricom JA, Morgan DR.
College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada.
Am J Clin Nutr 1995 Dec;62(6):1261-7

Green lentils are an increasingly popular food, but their effects on human colonic function and serum lipids have been studied little. Nine healthy males aged 19-38 y consumed for 3-wk periods a controlled Western diet and the same diet supplemented with 130 g dry lentils/d [which contained 11.8 g non-starch polysaccharide (NSP)] incorporated into loaves, cakes, and soups. Protein was equilibrated with soy protein isolate and carbohydrate with soft drinks. Radioopaque markers were used to calculate mean transit time (MTT) and to correct fecal weight for infrequency of bowel movements. Feces were collected throughout the study and blood was taken on 2 d at the end of each period. Lentils increased fecal weight from 131 +/- 12 g/d (means +/- SEM) to 189 +/- 17.4 g/d (44.9%) (P < 0.005). MTT was unchanged: 46 +/- 6 h for the control diet and 43 +/- 4 h for the lentils (NS). Fecal nitrogen was increased to 2.49 +/- 0.08 g/d for lentils compared with 1.74 +/- 0.09 g/d for the control diet (P < 0.001) and urine nitrogen decreased to 15.31 +/- 0.52 g/d with the lentils compared with 15.90 +/- 0.51 g/d for the control diet (P < 0.05); nitrogen balance was unaffected. Serum lipids were unchanged by addition of lentils to the diet. Green lentils were effective in increasing fecal weight and can therefore make a valuable contribution to a healthy diet.

Sustained slowing effect of lentils on gastric emptying of solids in humans and dogs.
Lin HC, Moller NA, Wolinsky MM, Kim BH, Doty JE, Meyer JH.
Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California.
Gastroenterology 1992 Mar;102(3):787-92

The distal small intestine is an especially potent site for carbohydrate-triggered intestinal inhibition of gastric emptying of solids. Poorly digestible carbohydrates, such as lentils, may escape proximal absorption, travel over time to reach these inhibitory mechanisms, and slow the gastric emptying of a later meal. A slowing effect on gastric emptying may be associated with a lowering effect on postprandial glucose. The aims of this study were to determine (a) whether lentils (a poorly digestible carbohydrate) vs. bread (an easily digestible carbohydrate) eaten as a premeal (with equal amounts of carbohydrates) slow the gastric emptying of a second solid meal taken 4.0-4.5 hours later and (b) whether a slowing effect on the gastric emptying of the second meal is associated with a lower postprandial glucose response. We found that in 7 dogs and 10 humans, gastric emptying of the second meal was delayed after a lentil premeal compared with a bread premeal. However, there was no difference in the glucose response to the second meal under the two conditions.

Large bowel fermentation in rats given diets containing raw peas (Pisum sativum).
Goodlad JS, Mathers JC.
Department of Agricultural Biochemistry and Nutrition, University of Newcastle upon Tyne.
Br J Nutr 1990 Sep;64(2):569-87

The digestion of non-starch polysaccharides (NSP) was studied in rats given semi-purified diets containing 0-500 g raw peas (Pisum sativum)/kg. NSP were equally well digested at all inclusion levels with digestibilities for individual constituents ranging from 0.58 for xylans to 0.99 for arabinose-containing polymers with a total NSP digestibility of 0.79. Increasing the dietary pea inclusion rate increased the amount of substrate flowing to the large bowel (LB) and this was associated with marked increases in caecal tissue and contents masses, a reduction in caecal transit time from 0.88 to 0.43 d and a threefold increase in faecal bacterial output. Caecal pH fell as did the molar proportions of acetate, isobutyrate, isovalerate and valerate whilst butyrate increased when peas were included in the diet. Possible mechanisms for these fermentation end-product changes are discussed. Pea inclusion in the diet was associated with increased volatile fatty acid and 3-hydroxy butyrate concentrations in portal and heart blood. It was concluded that peas are a rich source of fermentable polysaccharides which produce a LB fermentation pattern of potential health benefit.

Carbohydrate fractions of legumes: uses in human nutrition and potential for health.
Guillon F, Champ MM.
URPOI & UFDNH, National Institute for Agronomic Research (INRA), Rue de la Geraudiere, BP 71627, 44316 Nantes Cedex, 03, France. guillon@nantes.inra.fr
Br J Nutr 2002 Dec;88 Suppl 3:S293-306

Starch and fibre can be extracted, using wet or dry processes, from a variety of grain legumes and used as ingredients for food. alpha-Galactosides can be isolated during wet processes from the soluble extract. Starch isolates or concentrates are mostly produced from peas, whereas dietary fibre fractions from peas and soyabean are commercially available. The physico-chemical characteristics of fibre fractions very much depend on their origin, outer fibres being very cellulosic whereas inner fibres contain a majority of pectic substances. Inner fibres are often used as texturing agents whereas outer fibres find their main uses in bakery and extruded products, where they can be introduced to increase the fibre content of the food. Most investigations on impacts on health have been performed on soyabean fibres. When positive observations were made on lipaemia, glucose tolerance or faecal excretion, they were unfortunately often obtained after non-realistic daily doses of fibres. Legume starches contain a higher amount of amylose than most cereal or tuber starches. This confers these starches a lower bioavailability than that of most starches, when raw or retrograded. Their low glycaemic index can be considered as beneficial for health and especially for the prevention of diseases related to insulin resistance. When partly retrograded, these starches can provide significant amount of butyrate to the colonic epithelium and may help in colon cancer prevention. alpha-Galactosides are usually considered as responsible for flatus but their apparent prebiotic effects may be an opportunity to valorize these oligosaccharides.

Impact of tofu or tofu + orange juice on hematological indices of lacto-ovo vegetarian females.
Kandiah J.
Department of Family and Consumer Sciences, Ball State University, Muncie, IN 47306, USA. jkandiah@gw.bsu.edu
Plant Foods Hum Nutr 2002 Spring;57(2):197-204

The purpose of this study was to investigate iron status of premenopausal vegetarian women consuming tofu or tofu plus orange juice. Following a three day pre-period, 14 lacto-ovo vegetarians were randomly divided into two experimental periods of 30 days each. For the first 30 days, one half of the subjects (n = 7) received 6 oz (173 grams) of tofu/day (T) while the other half of the subjects (n = 7) received 6 oz of tofu/day along with 303 mg of vitamin C/d (TO). After 30 days, there was a crossover of the diets. Iron status was assessed by measuring serum ferritin and hemoglobin concentrations on the first day of the study and at the end of each experimental period. The Mann Whitney-U test was significant during the first (W = 17.5; Z = -2.095; p = 0.0361) and over the second (W = 40.0; Z = -2.611; p = 0.009) experimental periods which indicated the change in hemoglobin levels for the T and TO groups were different. Mean ranks showed a greater increase in hemoglobin levels for the TO group. There was no significant difference in the change in serum ferritin levels between the T and TO groups over the first and second experimental periods. In conclusion, bioavailability of iron from tofu is enhanced by supplementation with ascorbic acid.

Tofu consumption and blood lead levels in young Chinese adults.
Chen C, Wang X, Chen D, Li G, Ronnenberg A, Watanabe H, Wang X, Ryan L, Christiani DC, Xu X.
Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA.
Am J Epidemiol 2001 Jun 15;153(12):1206-12

Tofu is a commonly consumed food in China. Tofu may interfere with lead absorption and retention because of its high calcium content. In this observational study, the authors examined whether dietary tofu intake was associated with blood lead levels among young adults in Shenyang, China. The analyses included 605 men and 550 women who completed baseline questionnaires and had blood lead measurements taken in 1996-1998 as part of a prospective cohort study on reproductive health. Mean blood lead levels were 13.2 microg/dl in men and 10.1 microg/dl in women. Blood lead levels were negatively associated with tofu intake in both genders. A linear trend test showed a 3.7% (0.5-microg/dl) decrease in blood lead level with each higher category of tofu intake (p = 0.003). The highest tofu intake group (> or =750 g/week) had blood lead levels 11.3% lower (95% confidence interval: 4.1, 18.0) than those of the lowest tofu intake group (<250 g/week). In all regression models, data were adjusted for gender, age, height, body mass index, district, cigarette smoking, alcohol drinking, education, occupation, use of vitamin supplements, season, and dietary intake of meat, fish, vegetables, eggs, and milk. In conclusion, the authors found a significant inverse dose-response relation between tofu consumption and blood lead levels in this Chinese population.

Brain aging and midlife tofu consumption.
White LR, Petrovitch H, Ross GW, Masaki K, Hardman J, Nelson J, Davis D, Markesbery W.
National Institute on Aging, NIH, USA.
J Am Coll Nutr 2000 Apr;19(2):242-55

OBJECTIVE: To examine associations of midlife tofu consumption with brain function and structural changes in late life. METHODS: The design utilized surviving participants of a longitudinal study established in 1965 for research on heart disease, stroke, and cancer. Information on consumption of selected foods was available from standardized interviews conducted 1965-1967 and 1971-1974. A 4-level composite intake index defined "low-low" consumption as fewer than two servings of tofu per week in 1965 and no tofu in the prior week in 1971. Men who reported two or more servings per week at both interviews were defined as "high-high" consumers. Intermediate or less consistent "low" and "high" consumption levels were also defined. Cognitive functioning was tested at the 1991-1993 examination, when participants were aged 71 to 93 years (n = 3734). Brain atrophy was assessed using neuroimage (n = 574) and autopsy (n = 290) information. Cognitive function data were also analyzed for wives of a sample of study participants (n = 502) who had been living with the participants at the time of their dietary interviews. RESULTS: Poor cognitive test performance, enlargement of ventricles and low brain weight were each significantly and independently associated with higher midlife tofu consumption. A similar association of midlife tofu intake with poor late life cognitive test scores was also observed among wives of cohort members, using the husband's answers to food frequency questions as proxy for the wife's consumption. Statistically significant associations were consistently demonstrated in linear and logistic multivariate regression models. Odds ratios comparing endpoints among "high-high" with "low-low" consumers were mostly in the range of 1.6 to 2.0. CONCLUSIONS: In this population, higher midlife tofu consumption was independently associated with indicators of cognitive impairment and brain atrophy in late life.

Cholesterol and bile acid balance in Macaca fascicularis. Effects of alfalfa saponins.
Malinow MR, Connor WE, McLaughlin P, Stafford C, Lin DS, Livingston AL, Kohler GO, McNulty WP.
J Clin Invest 1981 Jan;67(1):156-62

We determine the effects of alfalfa top saponins on cholesterol and bile acid balance in eight cynomolgus macaques (Macaca fascicularis). The monkeys ate semipurified food containing cholesterol with or without added saponins. The saponins decreased cholesterolemia without changing the levels of high density lipoprotein-cholesterol; hence, they reduced the total cholesterol/high density lipoprotein-cholesterol ratio. Furthermore, they decreased intestinal absorption of cholesterol, increased fecal excretion of endogenous and exogenous neutral steroids and bile acids, and decreased the percent distribution of fecal deoxycholic and lithocholic acids. The fecal excretion of fat was also slightly increased, but steatorrhea did not occur. We saw no signs of toxicity in the monkeys after 6 or 8 wk of saponin ingestion. The data suggest that alfalfa top saponins may be of use in the treatment of patients with hypercholesterolemia, but long-term studies on possible toxicity are needed before this therapy can be recommended for humans.

Comparative effects of alfalfa saponins and alfalfa fiber on cholesterol absorption in rats.
Malinow MR, McLaughlin P, Stafford C, Livingston AL, Kohler GO, Cheeke PR.
Am J Clin Nutr 1979 Sep;32(9):1810-2

Intestinal absorption of cholesterol was measured in control rats fed semipurified diets and in rats fed alfalfa meal, in which saponins had been previously extracted, or this extracted material plus alfalfa saponins. A dose of 2 mg radioactive cholesterol was administered intragastrically, and fecal excretion of labeled neutral steroids measured. Absorption of cholesterol was about 76% in control animals, and about 47% in alfalfa-red rats. Extraction of saponins from alfalfa eliminated the cholesterol absorption-lowering effect, while addition of 0.26% alfalfa saponins to the extracted alfalfa restored its activity. The results demonstrate that alfalfa saponins are responsible for the effect of alfalfa meal in reducing cholesterol absorption, and that alfalfa fiber is not involved in this activity.

Alfalfa seeds: effects on cholesterol metabolism.
Malinow MR, McLaughlin P, Stafford C.
Experientia 1980 May 15;36(5):562-4

Plasma cholesterol concentrations were reduced in 3 human volunteers during ingestion of diets containing alfalfa seeds (AS) for 3 weeks. No signs of toxicity were detected through serum determinations of multiple parameters. The ingestion of AS in rats decreased the concentration of plasma cholesterol, reduced intestinal absorption of exogenous and endogenous cholesterol, and increased fecal biliary excretion.