Green peas pack a surprisingly dense nutritional profile for such a small vegetable. A single cup of cooked green peas delivers meaningful amounts of plant protein, fiber, several B vitamins, vitamin K, and a range of minerals, all for relatively few calories. Here’s a closer look at what’s actually inside them.
Protein and Amino Acids
Peas are one of the better plant-based protein sources among vegetables. A cup of raw green peas contains roughly 8 grams of protein, and the quality of that protein is notable. About 8 to 9 percent of the total amino acids in peas come from lysine, an essential amino acid that many grains lack. Peas also contain the branched-chain amino acids leucine (8 to 9 percent), valine (5 to 6 percent), and isoleucine (3 to 4 percent), which play a role in muscle repair and energy production. This makes peas a useful complement to grains like rice or wheat, which are low in lysine but higher in the sulfur-containing amino acids that peas have less of.
Fiber: Mostly Insoluble
Peas are a solid source of dietary fiber, with a cup of cooked peas providing around 7 to 9 grams depending on whether they’re fresh or frozen. What’s interesting is the breakdown: roughly 74 percent of the fiber in green peas is insoluble, with only about 26 percent soluble. Insoluble fiber adds bulk to stool and helps move things through the digestive tract, while the smaller soluble portion forms a gel-like substance that can slow sugar absorption and support healthy cholesterol levels.
Per 100 grams of microwaved frozen peas, that works out to about 0.94 grams of soluble fiber and 2.61 grams of insoluble fiber. If you’re looking for a vegetable that keeps digestion regular, peas are a reliable pick.
Key Vitamins
Vitamin K is one of the standout nutrients. A half cup of cooked green peas delivers about 21 micrograms of vitamin K, which your body uses for blood clotting and bone metabolism. Peas also provide folate (vitamin B9), which is important for cell division and is especially relevant during pregnancy. Vitamin C is present in fresh and frozen peas as well, though amounts vary significantly depending on how you cook them (more on that below).
Several other B vitamins show up in meaningful quantities, including thiamine (B1) and niacin (B3), both of which help your body convert food into energy.
Minerals Worth Noting
A cup of raw green peas provides 2.13 mg of iron, 156.6 mg of phosphorus, 47.85 mg of magnesium, and 0.59 mg of manganese. Cooking reduces some of these values. Frozen peas that have been boiled and drained retain about 1.22 mg of iron, 61.6 mg of phosphorus, 17.6 mg of magnesium, and 0.22 mg of manganese per cup.
The iron in peas is the non-heme type, which your body absorbs less efficiently than the heme iron in meat. Eating peas alongside a source of vitamin C, like tomatoes or bell peppers, helps improve that absorption.
Phytonutrients and Antioxidants
Beyond the standard vitamins and minerals, peas contain a range of plant compounds that act as antioxidants. Researchers have identified over 115 different phenolic compounds in peas, including flavonoids like kaempferol and quercetin glycosides, along with anthocyanins and isoflavonoids. These compounds help neutralize free radicals, which are unstable molecules linked to chronic diseases like cardiovascular disease and type 2 diabetes.
Peas also contain saponins, a group of compounds that have drawn attention for both their potential health benefits and their role in giving pea protein its slightly bitter, astringent taste. One study found that a specific saponin in peas contributed more to astringency than to bitterness, which partly explains why pea protein isolates taste the way they do.
Glycemic Impact
Despite being starchier than many vegetables, green peas have a moderate glycemic index of 51, right at the border between low and medium. More useful is the glycemic load, which accounts for actual serving size. An 80-gram serving of green peas has a glycemic load of just 4, which is considered low. This means peas cause a relatively gentle rise in blood sugar, making them a reasonable choice for people managing blood sugar levels.
Antinutrients in Peas
Like other legumes, peas contain compounds called antinutrients that can interfere with how well your body absorbs certain minerals. Phytic acid binds to calcium, iron, zinc, magnesium, and copper in the gut, reducing their absorption. Lectins, another category, can disrupt nutrient absorption across the intestinal wall. The good news is that peas have relatively low levels of both compared to other pulses. Among Canadian pulses studied, peas had the lowest phytic acid content, and their lectin levels (2.73 to 11.07 HU/mg) were far below those found in beans (87 to 89 HU/mg).
Cooking substantially reduces both lectins and phytic acid. Soaking peas before cooking further lowers these levels, so by the time you eat cooked peas, the antinutrient content is much less of a concern.
How Cooking Method Affects Nutrients
The way you prepare peas matters, especially for heat-sensitive vitamins like vitamin C. Boiling peas causes a 40 to 55 percent loss of vitamin C after just five minutes, as the vitamin leaches into the cooking water. Steaming is far gentler, resulting in only 9 to 14 percent loss over the same time. If you’re eating peas for their vitamin C content, steaming or microwaving will preserve significantly more than boiling.
B vitamins are also water-soluble and follow a similar pattern, though they’re somewhat more heat-stable than vitamin C. Minerals like iron and phosphorus don’t break down from heat, but they can still leach into boiling water. The mineral data bears this out: a cup of boiled frozen peas retains only about 57 percent of the iron and 39 percent of the phosphorus found in the same amount of raw peas. Using minimal water or choosing steaming over boiling helps you keep more of what’s in the pea on your plate.