What Foods Cause Oxidative Stress?
Oxidative stress can cause a wide variety of health issues, from inflammation to heart disease, diabetes, and even cancer.
Diet plays an essential role in health, as the food you eat provides your cells, tissues, and organs with the nutrients they need to function well. Food also helps you manage oxidative stress, a natural process that can negatively affect your health. In fact, some foods can actually cause oxidative stress in ways that lead to health problems.
What Causes Oxidative Stress?
Oxidative stress develops when you have too many free radicals — unstable atoms or molecules that damage other atoms and molecules.
In a process known as oxidation, your body cells use oxygen to break down food molecules for energy. The metabolic process of breaking down food molecules can cause some atoms to lose electrons, which are negatively-charged particles that balance the positively-charged protons. Losing electrons causes the atoms and molecules to become unstable free radicals.
Free radicals try to stabilize themselves by stealing electrons from other atoms. Taking electrons away from those atoms creates more free radicals, which can cause widespread instability in cells, organs, and tissues.
Some free radicals contain oxygen atoms. Known as reactive oxygen species (ROS), these free radicals can damage DNA, proteins, and the body fats, known as lipids.
Antioxidants help keep the body balanced by providing free radicals with the electron they need without becoming free radicals themselves. Unfortunately, the body cannot always produce enough antioxidants to keep free radicals at healthy levels. Oxidative stress is a term that describes the state of having more free radicals than antioxidants. Left unaddressed, oxidative stress can disrupt body systems to cause ill health.
External factors, such as exposure to pollution or toxic pesticides, can trigger the development of free radicals and cause oxidative stress. Certain foods can also influence the balance of free radicals and antioxidants naturally.
Foods that Cause Oxidative Stress
What food causes oxidative stress? Some foods contribute to oxidative stress by either causing the production of free radicals or by reducing antioxidants – or both.
Fats and oils
Fats and oils may become oxidized after exposure to light, air, or heat during storage, for example, and this oxidation causes free radicals. Heating fat and oil to high temperatures during deep-frying may also cause oxidation.
Sugars and starches are refined carbohydrates that the body breaks down to use as fuel, creating free radicals as a byproduct. Eating a diet high in sugars and starches shifts the production of free radicals into overdrive. High-carbohydrate foods include:
- Soft pretzels
- Bread products
- Ice cream and milkshakes
- Soft drinks
The preservatives in processed meat may also contain free radicals. Processed meat includes:
- Hot dogs
- Corned beef
- Many deli meats
Alcohol increases the production of reactive oxygen species, reduces the level of antioxidants present in cells, and enhances oxidative stress in many body tissues, especially in the liver.
Foods that Improve Oxidative Stress
Some foods can improve oxidative stress because they contain vitamins, minerals, and chemicals that introduce antioxidants into the body. Antioxidant-rich foods include fruits and vegetables, whole grains, nuts and seeds, and spices. Cocoa, tea, and coffee also contain antioxidants that fight oxidative stress.
Broccoli, Brussels sprouts, cauliflower, cantaloupe, leafy greens, grapefruit, honeydew, kale, lemon, kiwi, orange, snow peas, papaya, sweet potato, strawberries, tomatoes, and bell peppers contain vitamin C, which is a potent antioxidant.
Vitamin E is another antioxidant that fights oxidative stress. Find vitamin E in avocados, almonds, Swiss chard, red peppers, leafy greens, peanuts, boiled spinach, and sunflower seeds.
Carotenoids give plants their color; carotenoids are also antioxidants. Beta-carotene is a carotenoid that gives carrots their orange color, for example, and lycopene makes tomatoes and pink grapefruit red. Other foods rich in carotenoids include apricots, asparagus beets, cantaloupe, watermelons, and bell peppers.
Selenium is a trace mineral found in Brazil nuts, shellfish, fish, beef, poultry, brown rice, and barley.
Zinc is an essential mineral in beef and poultry, shrimp, oysters, pumpkin seeds, sesame seeds, lentils, chickpeas, cashews, and fortified cereals.
Phenolic compounds help plants resist stress, and they can help humans fight oxidative stress. Several types of phenolic compounds exist in food, including:
- Quercetin in apples, red wine, and onions
- Catechins in tea, cocoa, and berries
- Resveratrol in red and white wine, grapes, peanuts, and berries
- Coumaric acid in spices and berries
- Anthocyanins in blueberries and strawberries
Consult with your healthcare or wellness professional for more information on what foods cause oxidative stress and foods that improve oxidative stress.