fenugreek seeds

What is fenugreek

Fenugreek, also known as its scientific name of trigonella foenum-graecum L., leguminosae, belongs to the plant family fabaceae (or leguminosae). It grows in most of the countries around world with major production in Asia, Europe and American including United States. Fenugreek is an herb extract prepared from the dried seeds of Trigonella foenum-graecum (sicklefruit fenugreek), a plant belonging to the pea family (Fabaceae) 1). Fenugreek is in the spice blend garam masala. It’s used to flavor imitation maple syrup and as a condiment 2). Its extracts are also in soaps and cosmetics 3). Fenugreek is native to India and northern Africa and is one of the oldest medicinal plants is continuous use. Historically, fenugreek was used for a variety of health conditions, in Chinese medicine, fenugreek seeds were used as a tonic; in Indian medicine, as a stimulant to lactation , including digestive problems and to induce childbirth; and, in many folk medicines as an aid to digestion and treatment of baldness. Today, fenugreek is used as a dietary supplement for diabetes, to stimulate milk production during breastfeeding, and for other health conditions 4). It’s also used topically as a dressing for wounds or eczema. The seeds are made into capsules, powders, teas, liquid extracts, and a dressing for the skin 5).

Investigation of its activity in animal models suggested that fenugreek extracts have antioxidant, antihyperlipidemic and hypoglycemic activities. Constituents of fenugreek extracts include dietary fibers, mucilages, steroid saponins, flavonoids, trigonelline, and volatile oils. The lipid- and glucose-lowering effects of fenugreek have been attributed to saponins.

  • A few small studies 6) found that fenugreek may help lower blood sugar levels in people with diabetes (type 2 diabetes mellitus), but the evidence is weak 7). There is thus good scientific evidence to support that fenugreek is not effective in lowering blood glucose in healthy, obese or overweight subjects 8), 9).
  • Some studies suggest 10), 11) —but haven’t proven—that fenugreek may increase milk production in women who are breastfeeding 12), 13).
  • There isn’t enough scientific evidence to support the use of fenugreek for any health condition 14).

The benefits of fenugreek therapy in hypercholesterolemia and diabetes in humans have not been proven in rigorously designed prospective clinical trials 15). Nevertheless, fenugreek is widely used, often in combination with conventional therapies. The usual doses used to aid in the management of diabetes and hypercholesterolemia are variable, ranging from 2 to 100 grams daily taken in 2 or 3 divided doses either as capsules or as powder to prepare teas. Fenugreek preparations contain high levels of fiber, which may represent 50% of its constituents. Fenugreek is also used topically and in foods as a flavoring agent.

Fenugreek uses

Four recent patents or patent applications described usages and applications of fenugreek in managing metabolic diseases including hyperglycemia and diabetes. One patent application described making dietary supplements with fenugreek fibers to control blood glucose 16). Another patent application claimed making food products with fenugreek seed powder for prevention of obesity and diabetes 17). The third patent application disclosed an anti-diabetic composition of food supplement with fenugreek seed extract 18). Clinical studies with human volunteers showed a dosage form of 500 mg given once or twice daily either alone or in combination with standard, synthetic anti-diabetic drugs such as metformin and glipizide provided beneficial effects on controlling plasma glucose levels. One recently issued patent illustrated a composition with fenugreek seeds to lower glucose and cholesterol 19).

Those claims are largely supported by the findings from human clinical trials. Four such trials were conducted with type 1 and 2 diabetic patients before 2000. The first study involved non-insulin dependent diabetic patients 20). Supplementation of 15 g fenugreek seed soaked in water resulted in a significant reduction in postprandial glucose levels in 21 diabetic patients. The second study was a randomized, controlled crossover trial with 15 diabetic patients 21). A diet supplemented with 100 g of fenugreek seed powder was given daily for 10 days in treatment group (7 patients) while a regular diet was given to the control group (8 patients). Then the patients were crossed over for additional 10 days. It was found that supplementation with fenugreek seed powder significantly reduced fasting blood sugar and improved the glucose tolerance test. In the third study, ten non-insulin dependent diabetic patients were enrolled in a randomized, controlled crossover trial 22). Treatment for 5 subjects included a diet supplemented with 25 g fenugreek daily for 15 days. Without a washout period, the patients were crossed over for additional 15 days. The results showed that fenugreek supplement significantly reduced the area under the plasma glucose curve and improved glucose tolerance. In the fourth trial 23), forty patients with coronary artery disease and non-insulin-dependent diabetes mellitus and 30 healthy volunteers were given a diet containing 5 g of fenugreek for 3 months. At the end of the study, twenty patients with mild hyperglycemia exhibited a significant reduction in fasting blood sugar and postprandial glucose levels. However, the changes in patients with severe hyperglycemia and healthy subjects were not statistically significant.

Four clinical trials were carried out more recently with diabetic patients. In a small double blind and controlled study 24), twenty five newly diagnosed type 2 diabetic patients were divided into two groups, treatment and control. Twelve patients in the treatment group were supplemented with 1 g hydroalcoholic extract of fenugreek seeds whereas 13 patients in the control group received placebo capsules for daily 2 months. No significant differences in fasting blood sugar and oral glucose tolerance test were detected between the two groups. However, significant differences in the area under curve of blood glucoses and insulin sensitivity were noticed. Two relatively large clinical trials were carried out in 2005 25) and 2008 26). One trial involved 60 male subjects with non-insulin dependent diabetes 27). Thirty patients in one group received a daily dose of 1 g mixed powder containing equal amount of raw fenugreek seed, bitter gourd and jambu seed powder in the form of capsules whereas the other group with 30 patients consumed same dose in the form of salty biscuits for 1.5 months, followed by ingesting an increased daily dose of 2 g mixed powder for another 1.5 months. At the end of the study, a significant reduction in fasting blood sugar and post-prandial glucose levels was achieved in both groups. The other trial was conducted in 69 type 2 diabetic patients with not well controlled blood glucose levels using oral sulfonylureas 28). The treatment group with 46 patients received 18 pills of fenugreek daily while the control group with 23 patients took placebo for 12 weeks. All the patients continued their original hypoglycemic drugs during the study. Supplement with fenugreek pills in the treatment group significantly decreased fasting blood sugar, postprandial blood glucose and HbA1c levels, coupled with improved clinical symptoms. It was thus concluded that supplementation of sulfonylureas hypoglycemic drug with fenugreek was an effective therapy to manage diabetic patients with uncontrolled blood glucose with hypoglycemic drug alone. The last trial recruited 18 type 2 diabetic patients 29). The subjects were divided into two groups. One group with 11 patients received a daily dose of 10 g fenugreek seed powder in hot water whereas the other group with 7 subjects consumed the same amount of fenugreek seeds mixed with yoghurt for 8 weeks. Significant decreases in fasting blood sugar was detected in group consuming fenugreek in hot water but not in the group given fenugreek mixed with yoghurt. It was concluded that fenugreek seeds was an effective adjuvant in the control of type 2 diabetes in the form of soaked in hot water. Mixing of fenugreek seeds with yoghurt may interfere with the absorption of active ingredients of fenugreek seeds in the gastrointestinal track.

The hypoglycemic activity of fenugreek was also evaluated in three clinical trials with healthy or healthy obese volunteers. The first early trial recruited 20 male healthy subjects 30). The treatment group received 40mg/kg aqueous extract of fenugreek seeds whereas the control group received placebo. Four hours post-ingestion, blood glucose levels were significantly reduced in the treatment group. The second trial was a single blind, randomized, crossover study and conducted in 18 healthy obese subjects 31). Two treatment groups received 4g or 8g of isolated fenugreek fiber whereas the control group received a placebo. No significant changes were noticed in postprandial blood glucose levels and insulin sensitivity within 3.5 hours post-ingestion between the three groups. The third trial is a double-blind, randomized, and placebo-controlled study with 38 healthy overweight male volunteers 32). Treatment group with 18 subjects received 1176mg daily dose of hydroalcohol extract of fenugreek seed for 6 weeks while the control group with 20 subjects received placebo. At the end of the study, no significant differences in fasting blood sugar and insulin were detected between the control and treatment group.

Taken together, the quality of trials with diabetic patients ranges from 0 to 3 Jadad Scale (Table 1). The Jadad scale, sometimes known as Jadad scoring or the Oxford quality scoring system, is a procedure to independently assess the methodological quality of a clinical trial. It is named after Colombian physician Alejandro Jadad-Bechara who in 1996 described a system for allocating the trial a score of between zero (very poor) and five (rigorous). Therefore, there is good scientific evidence (Level B2) suggesting that fenugreek is effective in reducing blood glucose levels in diabetic patients. The quality of trials with healthy, obese or overweight subjects ranges from 0 to 3 in the Jadad scale with majority of the trials exhibiting no hypoglycemic effect (Table 1).

In conclusion, a few small studies found that fenugreek may help lower blood sugar levels in people with diabetes (type 2 diabetes mellitus), but the evidence is weak 33). There is thus good scientific evidence to support that fenugreek is not effective in lowering blood glucose in healthy, obese or overweight subjects.

Table 1. Clinical Trials Evaluating the Hypoglycemic Effect of Fenugreek

Clinical TrialsSubjectsTreatmentsSizeHypoglycemic EffectJadad ScoreReference
Madar Z et al.Type 2 diabetic patientsFenugreek seeds, 15g21Yes034)
Sharma RD et al.Type 2 diabetic patientsFenugreek seeds, 100g/daily for 10 days15Yes135)
Raghuram TC et al.Type 2 diabetic patientsFenugreek seeds, 25g daily for 15 days10Yes136)
Bordia A et al.Type 2 diabetic patientsFenugreek seeds, 5g daily for 3 months40Yes/Noa037)
Gupta A et al.Type 2 diabetic patientsFenugreek seed extract, 1g daily for 2 months25Yes/Noa238)
Kochhar A et al.Type 2 diabetic patientsA composite supplement daily for 3 months60Yes139)
Lu FR et al.Type 2 diabetic patientsFenugreek extract, 18 pills daily for 12 weeks69Yes340)
Kassaian N et al.Type 2 diabetic patientsFenugreek seeds, 10g daily in water for 8 weeks11Yes041)
Kassaian N et al.Type 2 diabetic patientsFenugreek seed, 10g daily in yoghurt for 8 weeks7No042)
Abdel-Barry JA et al.Healthy volunteers40 mg/kg aqueous extract powder of Fenugreek seeds20Yes143)
Mathern JR et al.Healthy obese volunteers4 or 8g of isolated fenugreek fiber18No244)
Bordia A et al.Healthy volunteersFenugreek seeds, 5g daily for 3 months30No045)
Chevassus H et al.Healthy overweight volunteers1176mg fenugreek seed extract daily for 6 weeks38No346)
aOne of the following four measurements was significantly different between the treatment and control group: FBS, HbA1c, postprandial glucose levels and area under curve of blood glucose.
[Source 47)]

Fenugreek seeds

The seeds exhibit pungent aromatic properties 48); fenugreek is used as a spice in curry preparations 49), to flavour food, and to stimulate appetite. It has been observed that chronic oral administration of an ethanol extract of fenugreek (10 mg/day per 300 g body weight) increases food intake in rats, possibly due to the aromatic properties of the seeds 50). Fenugreek seeds are used in India, Egypt, and Yemen as a condiment and supplement in food, and its green leaves are widely consumed in India 51). The seeds are a good source of protein, but they also contain unavailable carbohydrates, mucilages, and saponins 52), 53). Three steroidal sapogenins (diosgenin, gitogenin, and tigogenin) were reported by Anis and Aminuddin 54), and 10 different sapogenins have been identified by analytical methods including coupled GC–MS 55). The biological properties of fenugreek saponins have been assessed 56) and they include hypocholesterolemic and antifungal activity as well as enhancement of food intake and feeding behaviour in rats 57). Among other alkaloids, trigonelline is found in the seeds 58). The seed contains a greater amount of minerals (Ca, P, Fe, Zn, and Mn) than other legumes 59). The lipid content of the seed (neutral lipids, glycolipids, and phospholipids) is approximately 7.5% 60). The aromatic constituents of fenugreek seeds include n-alkanes, sesquiterpenes, and oxygenated compounds such as hexanol and γ-nonalactone 61). The seeds also contain flavonoids, carotenoids, coumarins, and other components 62). The amino acid content is high in arginine, alanine, and glycine, but not in lysine 63); however, the nonprotein amino acid 4-hydroxyisoleucine (4-OHIle) is abundant in the seeds 64).

Fenugreek seed contains 30% soluble fibre and 20% insoluble fibre, which can slow the rate of postprandial glucose absorption, possibly as a secondary mechanism for the hypoglycaemic effect. Doses ranging from 2.5 g to 15 g daily of crushed and defatted seeds have been used in clinical studies (crushing allows for the release of the viscous gel fibre that contributes to fenugreek’s efficacy), while the seeds have been used in the range of 1–3 g mixed with food. Diarrhoea and flatulence are the most common side effects observed, and the fibre can affect absorption of oral medications. As one of the major effects of fenugreek is decreased blood glucose, careful monitoring of glucose levels is needed when it is taken concomitantly with insulin or other glucose-lowering agents. Fenugreek can also exhibit anticoagulant activity; therefore, it should be used under close medical supervision when anticoagulant agents are prescribed 65), 66), 67). A decrease of serum triglycerides (TGs), total cholesterol, and low-density lipoprotein cholesterol (LDL-C) is observed with fenugreek seed administration. This may be due to the presence of sapogenins, which increase biliary cholesterol excretion, resulting in reduced serum cholesterol levels 68). The U.S. Food and Drug Administration, with regard to food ingredients, has determined that fenugreek seed extracts are not genotoxic (based on a minimum content of 40% nonprotein amino acid 4-hydroxyisoleucine [4-OHIle]) 69).

Amino acid 4-hydroxyisoleucine [4-OHIle] is a branched-chain amino acid only present in plants. It is particularly abundant in fenugreek seeds (0.015%–0.4%) 70). It is synthesised from isoleucine and has been postulated as one of the molecules responsible for the antidiabetic effects in animals because of its ability to regulate pancreatic insulin secretion 71), hence it has significant potential for the treatment of insulin resistance and diabetes 72). The antidiabetic properties of amino acid 4-hydroxyisoleucine [4-OHIle] are related to its ability to stimulate insulin secretion, as observed in human pancreatic islet cells, in isolated perfused rat pancreas 73) and in in vivo studies 74). An improvement in glucose and insulin tolerance, insulin secretion, and reduced hyperglycaemia were observed in diabetic rats and dogs. Amino acid 4-hydroxyisoleucine [4-OHIle] functioned as an insulin secretagogue, but only in the presence of elevated blood glucose concentrations, in a range of 8.3–16.7 mM 75). Due to the fact that amino acid 4-hydroxyisoleucine [4-OHIle] acts as an insulin secretagogue in the presence of elevated blood glucose concentrations, it has been proposed for the potential treatment of insulin resistance, diabetes and obesity. The beneficial effects observed are related to the regulation of blood glucose, plasma triglycerides, total cholesterol, free fatty acid levels, and the improvement of liver function. The mechanism of action is related to increased Akt phosphorylation and reduced activation of Jun N-terminal kinase (JNK)1/2, extracellular signal-regulated kinase (ERK)1/2, p38 mitogen-activated protein kinase (MAPK), and nuclear factor (NF)-κB 76).

The hypocholesterolemic and antioxidant activities of various extracts (water, methanol, ethyl acetate, hexane, dichloro-methane) of fenugreek seeds were investigated in cholesterol-fed rats 77). Only the ethyl acetate extract reduced total cholesterol, triglycerides, and low-density lipoprotein cholesterol (LDL-C) and increased high-density lipoprotein cholesterol (HDL-C) compared with those of rats fed a cholesterol-rich diet. The phenolic and flavonoïd contents were highest in the methanol and the ethyl acetate extracts. These results showed that the ethyl acetate extract of the fenugreek seeds had a significant hypocholesterolemic effect and antioxidant activity in cholesterol-fed rats, whether this is partly due to the presence of flavonoïds in the extract needs further study 78).

Fenugreek has shown to be a useful remedy in combating abnormal cholesterol profiles in hyperlipidemic populations. A daily dose of fenugreek seed administered to rats (100 or 500 mg/kg) for eight weeks lowered LDL, VLDL triglyceride and total cholesterol and increased HDL when compared to a control group 79). Fasting cholesterol and triglyceride levels were similar across groups when fed either a high-cholesterol diet with fenugreek extract or a standard diet 80), and post-prandial triglyceride levels were higher in rats on the standard diet 81) concluding that fenugreek reduces triglyceride levels in fasting and post-prandial states in rats.

The mechanisms by which fenugreek may lower blood glucose levels have not been well established in humans. Acute hypoglycemic effects of fenugreek seeds and its extract have been evaluated in individuals with and without diabetes 82), 83), 84). Whole fenugreek raw seeds, extracted seed powder, cooked seeds (25 g) and gum isolate of seeds (5 g) decreased postprandial glucose levels, whereas degummed seeds (25 g) showed little effect 85). These findings suggest that acute effects of fenugreek seeds are mainly due to the gum fraction, but do not exclude a longer term effect of other fenugreek components on glycemia. Animal studies also indicate that the soluble fiber fraction of fenugreek seeds reduces the rate of enzymatic digestion and the absorption of glucose from the gastrointestinal tract 86). However, data from other studies suggest an effect of other fenugreek components on glucose homeostasis. In diabetic rats, trigonelline ingestion increased insulin sensitivity and reduced blood glucose levels 87). In addition, a novel amino acid derivative extracted from fenugreek seeds, amino acid 4-hydroxyisoleucine [4-OHIle], stimulated glucose-dependent insulin release in isolated rat and human pancreatic islet cells 88). In a trial of acute effects in healthy volunteers, trigonelline reduced the early glucose response during an oral glucose tolerance test 89). This systematic review and meta-analysis 90) suggest that fenugreek seeds may contribute to better glycemic control in persons with diabetes mellitus with a similar magnitude of effect as intensive lifestyle 91) or other pharmaceutical treatment added to standard treatment 92).

There is also evidence linking fenugreek to reduced hepatic cholesterol levels and elevated hepatic triglyceride lipase activity 93), the enzyme accountable for catabolizing chylomicrons and VLDL’s to smaller remnant particles 94). Mitigation of hepatic steatosis by reducing triglyceride accumulation in the liver 95) and prevention of ethanol-induced toxicity and apoptosis in liver cells 96) are other recent discoveries attributable to fenugreek. An aqueous herbal extract containing fenugreek lowered alanine aminotransferase (ALT), aspartate aminotransferase (AST), and glucose values, signifying a reduction in inflammation and a feasible protective agent against alloxan-induced oxidative stress and diabetes 97).

fenugreek

Table 2. Fenugreek seed nutritional facts

[Source: United States Department of Agriculture Agricultural Research Service 98)]

Fenugreek for breastfeeding

Fenugreek, has been widely cultivated in Asia, Africa and Mediterranean countries for the edible and medicinal values of its seeds. Breast milk is considered the optimal food source for newborns through 1 year of age. Many factors influence overall maternal production, including maternal pain, illness, balance of time when returning to work, anxiety, or emotional stress. Fenugreek, and milk thistle have shown mixed results in improving milk production; however, the trials were small and had a variety of limitations 99).

Some studies suggest 100), 101) —but haven’t proven—that fenugreek may increase milk production in women who are breastfeeding 102), 103).

Fenugreek side effects

Side effects of oral fenugreek are minor and include gastrointestinal upset, nausea, diarrhea, bloating, flatulence, and allergic reactions with facial edema, wheezing, dizziness and shock.

Despite being widely used, fenugreek has not been implicated in cases of clinically apparent liver injury and, in prospective studies, has had no effect on serum enzyme levels. In vitro studies have demonstrated hepatoprotective activity of fenugreek extracts in several animal models. Fenugreek can also exhibit anticoagulant activity; therefore, it should be used under close medical supervision when anticoagulant agents are prescribed 104), 105), 106). Because of the high fiber content, estrogenic and coumadin-like effects of fenugreek, it has a potential to cause herb-drug interactions particularly if taken in high doses with antiplatelet drugs and warfarin.

What Do We Know About Fenugreek Safety ?

  • Do not take fenugreek while pregnant because it may affect uterine contractions.
  • Fenugreek may act like estrogen in the body and be unsafe for women with hormone-sensitive cancers. Earlier reports show that fenugreek seeds provide a mastogenic effect resulting in enhanced breast size. This study provided the evidence for estrogenic activities on breast cancer cells of fenugreek seeds 107).
  • Side effects of fenugreek may include diarrhea; a maple-like smell to urine, breast milk, and perspiration; and a worsening of asthma.
  • There’s little information on the risks of taking fenugreek while breastfeeding.
  • Fenugreek should not be used in place of conventional medical care or to delay seeking care if you have health problems. This is particularly true if you have diabetes.

Summary

In humans, fenugreek seeds acutely reduced postprandial glucose and insulin levels 108), 109). In addition, several longer-term clinical trials showed reductions in fasting and post-prandial glucose levels and glycated haemoglobin (HbA1c) 110), 111), 112), but some trials did not show benefit 113), 114). Systematic reviews that have evaluated the effect of various alternative therapies for diabetes included only a few clinical trials of fenugreek 115), 116), 117). The mechanisms by which fenugreek may lower blood glucose levels have not been well established in humans. In this meta-analysis 118) of 10 clinical trials a significant reduction in glucose parameters for trials that administered medium to high doses (≥5 g) of fenugreek seed powder and not for trials that administered low doses (< 2 g) of hydro-alcoholic extracts. Medium to high doses (range: 5–25 g) of fenugreek seed powder also lowered postprandial glucose levels in acute studies 119), 120). None of the trials reported the methods of randomization or allocation concealment, and only a few trials provided information on blinding status and drop-out rates. In addition, with some exceptions 121) it was unclear whether other diabetes medication remained constant during the trial. Whole fenugreek raw seeds, extracted seed powder, cooked seeds (25 g) and gum isolate of seeds (5 g) decreased postprandial glucose levels, whereas degummed seeds (25 g) showed little effect 122). A systematic review and meta-analysis suggest that fenugreek seeds may contribute to better glycemic control in persons with diabetes mellitus with a similar magnitude of effect as intensive lifestyle 123) or other pharmaceutical treatment added to standard treatment 124).

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