What is E302?

Complete guide to understanding calcium ascorbate in your food

The Quick Answer

E302 is calcium ascorbate, a form of vitamin C used as an antioxidant and preservative in processed foods.

It’s a calcium salt of ascorbic acid that prevents food from browning, oxidizing, and spoiling while adding nutritional value.

Because it’s essentially vitamin C with added calcium, most people consume it regularly without realizing they’re getting a vitamin supplement.

What Exactly Is It?

E302 is calcium ascorbate, which is essentially vitamin C (ascorbic acid) bonded with calcium. The chemical formula is C₆H₇CaO₆, and it appears as a white to pale yellow crystalline powder with a slight citrus-like smell.

The name comes from its composition: it’s the calcium salt of ascorbic acid. Ascorbic acid (vitamin C) is naturally found in citrus fruits, berries, and vegetables. However, E302 is manufactured in a laboratory by combining ascorbic acid with calcium compounds, creating a more stable form that works better in food.

Unlike pure ascorbic acid (E300), which can be acidic and irritate sensitive stomachs, calcium ascorbate is “buffered”—meaning it’s gentler on the digestive system while providing the same antioxidant benefits plus added calcium. In chemical terms, it’s an inorganic salt. Your body absorbs it efficiently and uses it like natural vitamin C.

Where You’ll Find It

E302 appears in an extensive range of foods:

– Cured and processed meats (ham, bacon, sausages)
– Baked goods and pastries
– Breakfast cereals
– Fruit and vegetable drinks, juices
– Frozen fruits and vegetables
– Canned fruits and vegetables
– Dairy products and milk
– Baby foods and infant formulas
– Sauces and condiments
– Pizza bases
– Ice cream and frozen desserts
– Olives and pickled products
– Concentrated fruit juices

E302 is one of the most commonly used food additives globally. If you eat any processed food, you’ve almost certainly consumed it.

Why Do Food Companies Use It?

E302 does several critical jobs that make food products safer, fresher, and more appealing:

1. Prevents oxidation (antioxidant function): The primary reason. E302 stops the chemical process called oxidation, which makes food go brown, rancid, or lose flavor. In cut fruits and vegetables, it prevents the browning that occurs when they’re exposed to air. In oils and fats, it prevents rancidity that would make products taste stale.

2. Preserves color and appearance: E302 prevents enzymatic browning in potato products, juices, and canned fruits, keeping them looking fresh and appetizing. This is especially important for foods that consumers judge by appearance.

3. Protects nutritional value: Vitamins A, E, thiamine, folic acid, and other nutrients degrade when exposed to oxygen. E302 protects these vitamins, maintaining the nutritional value of food longer.

4. Extends shelf life: By preventing oxidation and microbial growth, E302 keeps products fresh longer, reducing food waste and allowing distribution over wider areas.

5. Meat curing enhancement: In processed meats, E302 works with nitrite curing agents to develop color and flavor. It also inhibits the formation of nitrosamines (potentially harmful compounds that can form from nitrites during digestion).

6. Provides nutritional fortification: Unlike synthetic antioxidants, E302 actually provides vitamin C and calcium—nutrients the body needs. Many manufacturers highlight this on labels because it adds genuine health value.

7. Stability in acidic foods: E302 is more stable than pure ascorbic acid at the pH levels found in most foods, making it more effective at preventing degradation.

Without E302 and similar antioxidants, processed foods would spoil faster, lose nutritional value more quickly, turn brown and unappetizing, and become unsafe to consume within realistic shelf timeframes.

Is It Safe?

The official position: Yes, E302 is considered very safe by regulatory bodies worldwide.

The European Food Safety Authority (EFSA) has evaluated calcium ascorbate and concluded that it is safe at the reported use levels. Notably, the EFSA determined that no numerical Acceptable Daily Intake (ADI) limit is needed—meaning authorities consider it safe even at very high consumption levels.

The FDA has classified ascorbates (including E302) as “Generally Recognized As Safe” (GRAS). The Joint FAO/WHO Expert Committee on Food Additives (JECFA) also confirmed safety with no numerical limits.

Why E302 is so safe:

– It’s essentially vitamin C with calcium—both essential nutrients
– Your body uses it like natural vitamin C you’d get from food
– It’s been used safely for decades
– The amounts used in food are modest
– It’s water-soluble, so excess is excreted through urine
– No toxic effects have been observed in normal food use

Important considerations:

At very high doses (far exceeding what you’d get from food), vitamin C can theoretically promote kidney stone formation in susceptible people, interfere with blood sugar control in diabetics, or affect cardiovascular health. However, these concerns apply only to high-dose supplementation, not to food additive use.

The amounts of E302 in food are carefully regulated and designed to prevent excessive consumption. A person would need to consume an extraordinary amount of food to exceed the doses shown to cause any issues.

Natural vs Synthetic Version

E302 can be made in two ways:

Natural-derived version: Ascorbic acid extracted or derived from plant sources (like glucose from corn or other plants), then combined with calcium compounds. Some manufacturers emphasize using “naturally-derived” sources.

Purely synthetic version: Manufactured through complete chemical synthesis in a laboratory, typically from glucose derivatives combined with calcium.

Both are chemically identical—the calcium ascorbate molecule (C₆H₇CaO₆) is exactly the same regardless of its origin. Your body cannot distinguish between them. Both are equally safe and effective.

The marketing difference is more about consumer preference than actual product differences. What matters for your health is the amount you consume, not whether the vitamin C started as a plant or was synthesized from scratch.

Natural Alternatives

Want to avoid E302?

Some food companies use these alternative antioxidants:

– E300 (Ascorbic acid) – pure vitamin C, slightly more acidic
– E301 (Sodium ascorbate) – vitamin C with sodium instead of calcium
– E304 (Ascorbyl palmitate) – fat-soluble form of vitamin C for oils
– E315/E316 (Isoascorbic acid/erythorbic acid) – similar to vitamin C but lacks vitamin activity
– Natural vitamin C from plant extracts
– Rosemary extract – natural antioxidant
– Mixed tocopherols (vitamin E) – another form of antioxidant

Some products labeled “naturally preserved” or “natural antioxidants” use these alternatives instead of E302. However, some alternatives (like sodium ascorbate) add sodium which isn’t ideal for blood pressure management, while others (like isoascorbic acid) don’t provide vitamin C benefits. Manufacturers typically choose E302 because it offers the best balance of effectiveness, safety, and nutritional benefit.

The Bottom Line

E302 (calcium ascorbate) is one of the safest food additives available—essentially a food-grade form of vitamin C plus calcium. Regulatory agencies worldwide have approved it without numerical intake limits, recognizing that its benefits outweigh any theoretical risks at normal consumption levels.

Unlike many synthetic additives that don’t contribute to nutrition, E302 actually provides vitamin C and calcium—essential nutrients your body needs. You’re not just preserving food; you’re adding value.

Most people consuming E302 through normal diet experience no adverse effects whatsoever. It has been used safely in food for decades.

What you should do:

– Understand that E302 is essentially vitamin C with added calcium—a beneficial nutrient
– Know that it’s one of the safest food additives available
– Don’t worry about consuming it in normal food amounts
– Read labels if you want to identify which products contain it
– If you have kidney disease or take vitamin C supplements, discuss total vitamin C intake with your doctor
– Remember that regulatory approval reflects genuine safety, not just reluctant permission

E302 is a rare example of a food additive that genuinely improves both food safety and nutritional value. It’s a safe, beneficial ingredient that you can feel confident about encountering in your food.