After seeds from the fenugreek plant are harvested, they can be dried and used as a spice or crushed into powder and turned into a supplement. Fenugreek extract actually comes from the seeds. As a result, seeds and extract contain the same phytonutrients and fiber, along with similar health benefits. Consult your doctor before taking fenugreek supplements, as they may interact with medications and worsen some medical conditions.
Fenugreek seeds contain a type of soluble fiber called galactomannan. When mixed with water, galactomannan forms a gel that helps reduce levels of cholesterol and lower blood sugar. The same quality also makes it a good thickener in foods and beverages.
Galactomannan is easily extracted from the seed, so the extract may contain about the same amount as the seeds. Fenugreek seeds have about 1 gram of fiber per teaspoon, according to the U.S. Department of Agriculture. The amount in fenugreek extract varies depending on the extraction process, so check the label on the products you buy.
In addition to galactomannan, fenugreek contains phytochemicals that help lower cholesterol and blood sugar. Seeds and extract contain several different types of saponins, which are plant-based compounds that inhibit cholesterol absorption, reports the University of Michigan Health System.
You’ll also get phytochemicals known as alkaloids from both the seeds and the extract. Fenugreek is a good source of an alkaloid called trigonelline, which may reduce blood levels of glucose, according to a review published in the "Nutrition Journal" in January 2014.
In laboratory experiments, saponins show promise for stopping the growth of cancer cells, as reported in "Cancer Biology and Therapy" in February 2009. However, more research is needed before scientists will know if fenugreek seeds or extracts inhibit cancer growth in humans.
Fenugreek seeds also contain antioxidant flavonoids, which they seem to retain no matter how the seeds are processed. When seeds are freeze-dried then processed with solvents, the extracts still have strong antioxidant activity, according to a study published in "Food Chemistry" in 2013. Even when fenugreek seeds are soaked or roasted and milled into flour, the flour still retains flavonoids that are active antioxidants, noted the "Journal of Food Science and Technology" in February 2015.
While this flavonoid staying power indicates that fenugreek seeds and fenugreek extracts provide antioxidants, the amount you’ll get is seldom reported on the supplement or food label.
Do not use fenugreek supplements if you're pregnant, you have diabetes, or you’ve been diagnosed with a hormone-sensitive cancer, such as breast cancer. You should also avoid fenugreek if you take warfarin or other medications to prevent blood clots. In fact, fenugreek supplements may interact with other prescription medications, aspirin and ibuprofen, so talk to your doctor to be sure the supplements are safe.
Allergic reactions to fenugreek aren’t common, but they have been reported, according to Dartmouth-Hitchcock Norris Cotton Cancer Center. Seek immediate medical attention if you develop hives, have a hard time breathing, or your throat, lips, tongue or face become swollen.