Alfalfa sprouts are the young, freshly germinated shoots of the alfalfa plant (a member of the pea family), harvested just days after the seeds begin to grow. They’re thin, crispy, and mild-tasting, with wispy white stems and tiny green leaves. You’ll find them on sandwiches, in salads, and tucked into wraps at delis and health food restaurants. They’re one of the most popular types of sprouts sold in grocery stores, prized for being low in calories while offering a range of vitamins and minerals.
How Alfalfa Sprouts Are Grown
Alfalfa is originally a forage crop, grown worldwide as livestock feed. The sprouts you eat are simply the plant in its earliest stage of life, harvested before it matures. Growing them is straightforward, whether done commercially or at home in a mason jar.
The process starts by soaking about two tablespoons of seeds in cool water for 8 to 12 hours. After draining that initial soak water, you rinse and drain the seeds with cool water every 8 to 12 hours (two to three times per day). No soil is needed. Within five to six days, the sprouts are ready to harvest, ideally when the tiny leaves have opened and turned green. The entire process requires nothing more than seeds, water, a jar, and a mesh lid or cheesecloth for draining.
Nutritional Profile
A one-cup serving of raw alfalfa sprouts is light, weighing about 33 grams, and delivers a modest but varied nutritional punch. That cup contains roughly 1.3 grams of protein, 10 micrograms of vitamin K (important for blood clotting), about 12 micrograms of folate, nearly 3 milligrams of vitamin C, and small amounts of manganese. The calorie count is negligible, typically under 10 calories per cup.
These numbers aren’t dramatic on their own, but sprouts are rarely eaten for a single nutrient. Their value comes from adding a broad, low-calorie spectrum of micronutrients to meals that might otherwise lack fresh vegetables. They also contain plant compounds called saponins and isoflavones, which have attracted research interest for potential health effects beyond basic nutrition.
Potential Health Benefits
The saponins in alfalfa can bind to cholesterol in the digestive tract, which may reduce the amount of cholesterol your body absorbs. Research has shown that alfalfa plant saponins bind significant quantities of cholesterol both from solution and from the mixed micelles that form during digestion. Sprout saponins showed a lesser but still meaningful effect. Bile acid binding by other components of alfalfa may contribute equally to its cholesterol-lowering potential. Most of this research has been done in animal models and test tubes, so the size of the effect in people eating normal portions of sprouts remains unclear.
Animal studies have also explored alfalfa’s effects on blood sugar. In diabetic rats, aqueous alfalfa extract significantly reduced blood glucose levels and appeared to support repair of insulin-producing cells in the pancreas. Earlier research found that alfalfa extract could increase insulin secretion up to threefold. These results are promising but come from concentrated extracts given to lab animals, not from people eating sprouts on a sandwich.
Alfalfa is also a source of isoflavones, a type of phytoestrogen found in plants like soybeans and red clover. Isoflavones have been studied for their role in easing menopausal symptoms, though the evidence is stronger for soy-based isoflavones than for those from alfalfa specifically.
Food Safety Concerns
Alfalfa sprouts carry a well-documented risk of bacterial contamination that sets them apart from most other fresh vegetables. Between 1996 and 2016, approximately 46 outbreaks and 2,474 illness cases in the United States were linked to sprouts. The pathogens involved include Salmonella, E. coli O157:H7, other toxin-producing E. coli strains, and Listeria.
The reason sprouts are particularly risky is that the growing conditions they need (warm temperatures, high moisture, neutral pH, and abundant nutrients) are the same conditions that allow dangerous bacteria to multiply rapidly. If a seed carries even a tiny amount of contamination, those bacteria can bloom during the sprouting process. And because sprouts are almost always eaten raw, there’s no cooking step to kill pathogens before they reach your plate.
The FDA requires commercial sprout growers to treat seeds before sprouting, test spent irrigation water or in-process sprouts from every production batch for specific pathogens, and monitor their growing environments for Listeria. Sprouts cannot legally be shipped until pathogen tests come back negative. These rules have improved safety, but outbreaks still occur. People with weakened immune systems, young children, older adults, and pregnant women are generally advised to avoid raw sprouts entirely.
Who Should Avoid Alfalfa Sprouts
Beyond the general food safety concern, alfalfa sprouts contain an amino acid called L-canavanine that can stimulate the immune system and increase inflammation. For most people, this isn’t a problem. But for anyone with lupus or a similar autoimmune condition, it can trigger or worsen disease flares. The Johns Hopkins Lupus Center advises people with lupus to avoid alfalfa sprouts completely.
If you take blood-thinning medications, the vitamin K in alfalfa sprouts is worth noting. While a single cup contains a relatively small amount, eating sprouts regularly or in large quantities could affect how your medication works, since vitamin K plays a direct role in the clotting process those drugs are designed to manage.
Storing Sprouts Safely
Whether store-bought or homegrown, alfalfa sprouts should be refrigerated at or below 41°F at all times. Fresh sprouts look crisp with their buds firmly attached. If they develop a musty smell, turn dark, or feel slimy, discard them immediately. Even properly stored sprouts are highly perishable and are best used within a few days of purchase or harvest. All commercially packaged sprouts are required to carry a “Perishable, keep refrigerated” label.