What Happens When You Consume Too Much Carotene?

Over-consuming carotene-rich foods like carrots can lead to carotenemia, a benign condition causing yellow-orange skin discoloration. While this is not toxic, consuming high-dose beta-carotene supplements is potentially unsafe for certain individuals.

Quick Summary

Excessive dietary carotene causes a harmless yellow-orange skin discoloration known as carotenemia, not vitamin A toxicity. High-dose beta-carotene supplements, however, carry specific health risks, particularly for smokers and asbestos-exposed individuals.

Key Points

• Carotenemia is Harmless: Overconsumption of carotene from food causes a benign yellow-orange skin discoloration called carotenemia, which is not toxic and fades with dietary moderation.

• No Vitamin A Toxicity from Food: The body regulates the conversion of dietary carotene into vitamin A, making it impossible to overdose on vitamin A from eating too many carotene-rich foods.

• Supplements Can Be Dangerous: High-dose beta-carotene supplements, especially for smokers and those exposed to asbestos, have been linked to an increased risk of lung cancer.

• Jaundice is Different: Unlike carotenemia, the yellowing of skin and whites of the eyes (sclera) in jaundice indicates a more serious underlying liver condition.

• Balanced Diet is Key: The safest and most effective way to consume carotene is through a varied diet of colorful fruits and vegetables, rather than relying on supplements.

• Dietary Moderation is the Cure: For diet-induced carotenemia, the only treatment needed is to reduce the intake of carotene-rich foods, and the skin color will gradually return to normal.

What is Carotene and How Does the Body Use It?

Carotene is a plant pigment found in colorful fruits and vegetables that the body converts into vitamin A as needed. This conversion is regulated, preventing excessive vitamin A levels from dietary carotene. Carotene also acts as an antioxidant.

The Harmless Side Effect: Carotenemia

The most common effect of consuming too much carotene is carotenemia, a benign and reversible yellow-orange skin discoloration. This happens when excess fat-soluble carotene builds up in the skin's outer layer and fat.

• Discoloration is often seen on palms, soles, and around the nose.
• Unlike jaundice, the whites of the eyes do not turn yellow.
• Carotenemia from food is nontoxic and doesn't cause vitamin A poisoning due to the body's self-regulation.
• It's common in infants eating pureed carrots and squash.

Potential Dangers of Carotene Supplements

While dietary carotene is safe in excess, high-dose supplements can be risky for certain groups. Studies show synthetic beta-carotene supplements can be harmful.

• Smokers: Trials found high-dose beta-carotene increased lung cancer risk in male smokers.
• Asbestos Exposure: Individuals with asbestos exposure history also saw increased lung cancer risk with high-dose supplements.

These findings advise against synthetic beta-carotene supplements for general health in these populations.

Carotenemia vs. Hypervitaminosis A: A Critical Comparison

It's important to distinguish carotenemia from hypervitaminosis A. Carotenemia is from excess dietary provitamin A (like carotene), while hypervitaminosis A is from toxic levels of preformed vitamin A (retinol), usually from supplements.

Feature	Carotenemia (Excess Dietary Carotene)	Hypervitaminosis A (Excess Preformed Vitamin A)
Cause	Excessive intake of carotene-rich foods (e.g., carrots, sweet potatoes).	Excessive intake of preformed vitamin A, often from supplements or liver.
Toxicity	Nontoxic. The body regulates conversion to prevent overdose.	Toxic and potentially life-threatening. The body can't regulate absorption from supplements.
Skin Discoloration	Yellow-orange skin, particularly on palms, soles, and nasolabial folds.	Can cause dry, rough skin and cracked lips, but not the typical yellow-orange hue.
Eye Symptoms	Sclera (whites of the eyes) are unaffected.	Can cause blurred vision and changes in vision.
Other Symptoms	Generally asymptomatic beyond skin color change. Can cause mild digestive issues due to high fiber intake.	Severe headache, nausea, dizziness, muscle aches, and potential liver damage or coma in severe cases.
Resolution	Reversible by reducing dietary intake over several weeks to months.	Symptoms typically resolve after discontinuing supplementation, but some effects can be serious.

How to Manage Excessive Carotene Intake

Managing excessive carotene from food is simple.

1. Reduce Carotene-Rich Foods: Cut back on foods like carrots, sweet potatoes, and leafy greens. Moderation is key.
2. Eat a Balanced Diet: Diversify your vegetable intake for a wider range of nutrients.
3. Monitor Skin: Observe skin color changes; discoloration fades when intake is reduced.
4. Consult a Professional: If unsure about skin discoloration or have dietary concerns, see a healthcare provider or dietitian.

Conclusion

Consuming too much dietary carotene causes carotenemia, a harmless, temporary yellow-orange skin discoloration. This is not toxic due to the body's regulated conversion to vitamin A. However, high-dose beta-carotene supplements pose risks, especially for smokers. The best way to get carotene's benefits is through a varied diet of colorful plants.

For more on dietary vs. supplemental vitamin A, see the NIH fact sheet on Vitamin A and Carotenoids.

Frequently Asked Questions

Can eating too many carrots be dangerous?

Eating too many carrots is not dangerous and will not cause vitamin A toxicity because the body only converts dietary beta-carotene into vitamin A as needed. The most significant effect is a harmless yellow-orange skin discoloration called carotenemia.

What is the difference between carotenemia and jaundice?

Carotenemia is a harmless yellow-orange skin tone caused by excess carotene, with the whites of the eyes (sclera) remaining white. Jaundice, on the other hand, is a yellowish discoloration of both the skin and the sclera, signaling a more serious liver or gallbladder issue.

How can I tell if my skin discoloration is from carotene?

Carotenemia typically appears as a yellow-orange tint on the palms, soles, and face, while the whites of the eyes remain unchanged. If your sclera also appears yellow, or if you have other symptoms like fatigue or abdominal pain, you should consult a doctor.

Are beta-carotene supplements safe to take?

For most people, obtaining beta-carotene from food is recommended. High-dose synthetic beta-carotene supplements are considered possibly unsafe, especially for smokers or people exposed to asbestos, due to an increased risk of lung cancer.

How do you reverse carotenemia?

The condition is naturally reversible by reducing your intake of carotene-rich foods. It may take several weeks to months for your skin to return to its normal color, as the carotene slowly leaves your body's fatty tissue.

What foods are high in carotene?

Foods rich in carotene include carrots, sweet potatoes, pumpkin, butternut squash, cantaloupe, mangoes, spinach, kale, and other dark leafy greens.

Is carotenemia a sign of poor health?

Diet-induced carotenemia is not a sign of poor health and requires no medical treatment, as it is a benign condition. However, carotenemia can be associated with certain underlying medical conditions, such as hypothyroidism or diabetes, so a doctor's visit is recommended if the cause is unclear.