Bell Peppers

Bell peppers (Capsicum annuum) are the crisp, sweet, hollow peppers that come in green, yellow, orange, and red. They belong to the same plant species as chili peppers, but with one friendly difference: they carry no heat. A single genetic change stops them from making capsaicin, the compound that makes chilies burn, which is why you can eat a bell pepper raw by the handful. For their modest calorie count, they are one of the richest everyday sources of vitamin C you can put on a plate — a red bell pepper actually carries more vitamin C than an orange, gram for gram. This page explains what bell peppers are, walks through their nutrition in plain language, looks honestly at the research on their vitamin C and colorful plant pigments, sorts out the popular "nightshade" worry, and offers practical tips for picking, storing, and cooking them.

Table of Contents

  1. What Bell Peppers Are
  2. Nutritional Profile
  3. Vitamin C: Immunity, Skin & Collagen
  4. The Carotenoids and Eye Health
  5. Antioxidant & Anti-Inflammatory Research
  6. How Ripeness Changes the Nutrition
  7. Raw vs. Cooked
  8. The Nightshade Question
  9. How to Select and Store
  10. Safety and Who Should Take Care
  11. Research Papers
  12. Connections
  13. Featured Videos

What Bell Peppers Are

Botanically, a bell pepper is a fruit — the seed-bearing part of the Capsicum annuum plant — even though we treat it as a vegetable in the kitchen. The plant is native to Central and South America and has been cultivated for thousands of years. What makes the "bell" or "sweet" pepper distinct from its fiery cousins is not a separate species but a single gene.

Chili peppers make capsaicin, the molecule responsible for their burn. Bell peppers carry a non-working version of the gene that builds capsaicin (researchers call this gene Pun1), so they produce essentially none. That is the whole reason a bell pepper tastes sweet and grassy instead of hot. It is a natural, long-standing trait of these varieties, not something added or removed during processing.

Why the Colors Differ

The different colors are not always different varieties — often they are the same pepper at different stages of ripening. A pepper starts green and unripe. Left on the plant, it turns yellow, then orange, then deep red as it matures, the way a tomato reddens. As it ripens, its sugars rise and its pigments change, so the color you buy is a rough clue to both flavor and nutrition:

Some yellow and orange peppers are bred to stay that color and will not turn red, so color is a helpful guide rather than an exact rule.

Nutritional Profile

Bell peppers are mostly water — around 92 percent — which is why they are so low in calories and so crunchy. A 100-gram serving (a little over half a medium pepper) of raw red bell pepper supplies roughly 26 to 31 calories. Within that small package is a genuinely impressive amount of nutrition, led by vitamin C. The figures below are approximate and vary with color, ripeness, growing conditions, and storage, but they give an honest sense of what you are eating.

Per 100 grams of raw red bell pepper, you can expect roughly:

Beyond the vitamins and minerals, bell peppers carry a spread of plant compounds — carotenoids such as beta-carotene, lutein, zeaxanthin, and capsanthin, plus flavonoids like quercetin and luteolin. These pigments and polyphenols are what give the peppers their color and much of their antioxidant activity, and they are covered in their own sections below.

Vitamin C: Immunity, Skin & Collagen

Vitamin C is the headline nutrient in bell peppers, and it is one of the better-studied vitamins in nutrition. Our bodies cannot make it or store it in large amounts, so we need a steady supply from food. Bell peppers — especially red and yellow ones eaten raw — are one of the most efficient ways to get it.

What Vitamin C Actually Does

Vitamin C is a water-soluble antioxidant that helps protect cells from everyday oxidative wear. It also plays several specific, well-documented roles. In the immune system, it supports the barrier function of the skin, helps immune cells do their job, and is used up faster during infection; reviews of the evidence describe vitamin C as contributing to normal immune defense, though it is not a cure for the common cold.

Perhaps its most famous job is building collagen, the protein scaffold that holds skin, blood vessels, gums, and connective tissue together. Vitamin C is a required helper for the enzymes that assemble collagen, which is why a severe deficiency (scurvy) causes bleeding gums and poor wound healing. For skin specifically, adequate vitamin C supports collagen production and helps defend the skin against oxidative stress. You do not need a supplement to get these benefits if you eat vitamin-C-rich foods like peppers regularly.

Getting the Most From It

Vitamin C is fragile. It dissolves in water and breaks down with heat, light, and long storage. That is the single best argument for eating at least some of your peppers raw and fresh — sliced into a salad, dipped in hummus, or added to a wrap — where the vitamin C survives intact.

The Carotenoids and Eye Health

The vivid colors of bell peppers come largely from carotenoids, a family of fat-soluble plant pigments. Different colors carry different carotenoids, and several of them matter for human health.

Beta-Carotene (Vitamin A)

Red and, to a lesser degree, orange peppers contain beta-carotene, which the body can convert into vitamin A as needed. Vitamin A is essential for vision in dim light, for the health of the skin and the surfaces lining the body, and for immune function. Because the body only converts as much as it needs, getting vitamin A this way — from colorful plants — does not carry the overdose risk that high-dose preformed vitamin A supplements can.

Lutein and Zeaxanthin

Bell peppers also supply lutein and zeaxanthin, two carotenoids that the body concentrates in the macula, the central part of the retina. There they act as a natural blue-light filter and antioxidant. Green and orange peppers tend to carry more of these two pigments than red ones — orange bell peppers are a particularly good source of zeaxanthin. In a large clinical trial, a supplement containing lutein and zeaxanthin modestly slowed the progression of advanced age-related macular degeneration in people at high risk, and broader reviews link higher dietary intake of these carotenoids with better long-term eye health. Peppers are one pleasant way to add them to a diet alongside leafy greens.

Capsanthin, the Red Pigment

The deep red of a ripe bell pepper comes mostly from capsanthin, a carotenoid that peppers and paprika are especially rich in. Capsanthin is a strong antioxidant in laboratory studies and is being explored for other effects, though most of that work is early and done in cells or animals rather than people. For now it is best thought of as one of the reasons a red pepper is more than just a sweeter green one.

Antioxidant & Anti-Inflammatory Research

Put the vitamin C, the carotenoids, and the flavonoids together and bell peppers show meaningful antioxidant capacity in the laboratory. When researchers measured the antioxidant activity of different-colored sweet bell peppers, the colored (riper) peppers generally out-performed green ones, tracking with their higher levels of vitamin C and carotenoids. Studies isolating the phenolic compounds from Capsicum fruit confirm that these plant chemicals, not just the vitamin C, contribute to the antioxidant effect.

It is worth being honest about what this does and does not mean. "High antioxidant activity in a test tube" is a promising signal, but it is not the same as a proven benefit inside the human body, where absorption, dose, and metabolism all intervene. The strongest, most practical case for bell peppers is not any single miracle compound — it is that they are a low-calorie, high-nutrient vegetable that helps fill out the kind of colorful, plant-rich diet that is consistently linked with better health. Eating the rainbow is good advice, and peppers make it easy and tasty.

How Ripeness Changes the Nutrition

One of the most useful things to know about bell peppers is that ripeness changes their nutrition, and red is generally the winner. As a pepper matures on the plant from green to red, several things happen at once: its sugar content climbs (so it tastes sweeter), its vitamin C tends to rise, and it develops the red and orange carotenoid pigments — including beta-carotene and capsanthin — that a green pepper barely has.

Studies that tracked pepper cultivars across their maturity stages found that phytochemical content and antioxidant activity shift substantially as the fruit ripens, with riper peppers usually carrying more of the beneficial compounds. In practical terms:

None of the colors is a "bad" choice — a green pepper is still a genuinely healthy food. But if you are choosing for maximum nutrition per bite, reach for the red ones. They cost more partly because they spend longer on the plant to ripen.

Raw vs. Cooked

There is no single "best" way to eat a bell pepper, because raw and cooked each protect a different nutrient.

The Case for Raw

Vitamin C is heat-sensitive and water-soluble, so cooking — especially boiling — can wash it away or break it down. If vitamin C is what you are after, raw peppers deliver the most. This is why fresh pepper strips are such a good snack: nothing is lost between the plant and your plate.

The Case for Cooked

The carotenoids — beta-carotene, lutein, capsanthin — are a different story. They are fat-soluble and are held inside the plant's cell walls. Gentle cooking softens those cell walls and can make the carotenoids easier for the body to absorb, and eating them with a little oil helps even more, because these pigments need fat to be taken up. Roasting, sauteing, or lightly grilling peppers can therefore boost the availability of their colorful pigments even as it trims some vitamin C.

The Simple Answer

Eat them both ways. General reviews of how cooking affects vegetables show the same trade-off across many foods: heat tends to lower vitamin C while sometimes improving carotenoid availability. Rotating between raw peppers in salads and roasted peppers in cooked dishes gives you the best of both. When you do cook them, favor quick, low-water methods — roasting, stir-frying, grilling — over long boiling, and add a drizzle of olive oil.

The Nightshade Question

Bell peppers belong to the nightshade family (Solanaceae), along with tomatoes, potatoes, and eggplant. You may have heard that nightshades "cause inflammation" or worsen arthritis, and that they should be avoided. It is worth looking at this claim honestly.

For the large majority of people, there is no good scientific evidence that bell peppers worsen arthritis, joint pain, or general inflammation. The idea is popular in some diet circles, but well-designed studies supporting a nightshade-inflammation link in the general population are essentially lacking. In fact, peppers are rich in the very antioxidant and anti-inflammatory plant compounds that a healthy diet is built on. Removing a nutritious vegetable on the basis of an unproven theory has its own cost.

That said, a small number of people do have a genuine sensitivity or allergy to peppers or other nightshades, and individuals with certain conditions occasionally report that specific foods bother their symptoms. Food reactions are real and personal. If you suspect peppers affect you, the sensible approach is a careful, temporary elimination and reintroduction — ideally with a doctor or dietitian — rather than assuming an entire food family is harmful. For most people, bell peppers are a healthy food, not an inflammatory one. Readers who want to dig into the primary literature can review the current evidence on PubMed: nightshade vegetables, inflammation, and arthritis.

How to Select and Store

Good bell peppers are easy to spot and easy to keep.

Choosing

Storing

Safety and Who Should Take Care

Bell peppers are a whole food and are safe and healthy for nearly everyone, with only a few practical notes.

For almost everyone, the bottom line is simple and cheerful: bell peppers are a colorful, low-calorie, vitamin-C-packed vegetable that is easy to enjoy raw or cooked, and there is little reason to hold back.

Research Papers

  1. Carr AC, Maggini S. Vitamin C and immune function. Nutrients. 2017;9(11):1211. doi:10.3390/nu9111211 — comprehensive review of how vitamin C supports the immune system, the nutrient peppers are richest in.
  2. Pullar JM, Carr AC, Vissers MCM. The roles of vitamin C in skin health. Nutrients. 2017;9(8):866. doi:10.3390/nu9080866 — explains vitamin C's role in collagen synthesis and protecting the skin from oxidative stress.
  3. Lee SK, Kader AA. Preharvest and postharvest factors influencing vitamin C content of horticultural crops. Postharvest Biol Technol. 2000;20(3):207-220. doi:10.1016/S0925-5214(00)00133-2 — shows how ripeness, storage, and handling change the vitamin C in produce like peppers.
  4. Sun T, Xu Z, Wu CT, Janes M, Prinyawiwatkul W, No HK. Antioxidant activities of different colored sweet bell peppers (Capsicum annuum L.). J Food Sci. 2007;72(2):S98-S102. doi:10.1111/j.1750-3841.2006.00245.x — directly compares the antioxidant capacity of green, yellow, orange, and red bell peppers.
  5. Howard LR, Talcott ST, Brenes CH, Villalon B. Changes in phytochemical and antioxidant activity of selected pepper cultivars (Capsicum species) as influenced by maturity. J Agric Food Chem. 2000;48(5):1713-1720. doi:10.1021/jf990916t — documents how carotenoids and antioxidant activity rise as peppers ripen.
  6. Materska M, Perucka I. Antioxidant activity of the main phenolic compounds isolated from hot pepper fruit (Capsicum annuum L.). J Agric Food Chem. 2005;53(5):1750-1756. doi:10.1021/jf035331k — identifies the phenolic plant compounds behind peppers' antioxidant effects.
  7. Maoka T. Carotenoids as natural functional pigments. J Nat Med. 2020;74(1):1-16. doi:10.1007/s11418-019-01364-x — reviews carotenoid pigments including capsanthin, the compound that makes ripe peppers red.
  8. Grune T, Lietz G, Palou A, et al. β-Carotene is an important vitamin A source for humans. J Nutr. 2010;140(12):2268S-2285S. doi:10.3945/jn.109.119024 — explains how the body converts the beta-carotene in red peppers into vitamin A.
  9. The Age-Related Eye Disease Study 2 (AREDS2) Research Group. Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration. JAMA. 2013;309(19):2005-2015. doi:10.1001/jama.2013.4997 — landmark trial of the eye-protective carotenoids that peppers also supply.
  10. Bernstein PS, Li B, Vachali PP, et al. Lutein, zeaxanthin, and meso-zeaxanthin: the basic and clinical science underlying carotenoid-based nutritional interventions against ocular disease. Prog Retin Eye Res. 2016;50:34-66. doi:10.1016/j.preteyeres.2015.10.003 — reviews how lutein and zeaxanthin protect the retina.
  11. Palermo M, Pellegrini N, Fogliano V. The effect of cooking on the phytochemical content of vegetables. J Sci Food Agric. 2014;94(6):1057-1070. doi:10.1002/jsfa.6478 — the raw-versus-cooked trade-off: heat lowers vitamin C but can improve carotenoid availability.
  12. Stewart C Jr, Kang BC, Liu K, et al. The Pun1 gene for pungency in pepper encodes a putative acyltransferase. Plant J. 2005;42(5):675-688. doi:10.1111/j.1365-313X.2005.02410.x — identifies the gene whose non-working form makes bell peppers sweet and capsaicin-free.

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Connections

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