Debunking The Truth About Antioxidants and Their Health Benefits

Introduction

Antioxidants have gained significant popularity in recent years due to their promising health benefits. People are increasingly exploring naturally found phytochemicals in our foods for their antioxidant effects, which can be good for our bodies. The media often shows oxidants as harmful and antioxidants as helpful protectors, which has made more people curious and eager to learn about them.

In 2024, the global antioxidants market was valued at USD 4.84 billion and is projected to grow from USD 5.11 billion in 2025 to USD 7.64 billion by 2032. The Asia-Pacific region dominates with a 43.8% market share.

While antioxidants are gaining popularity, it’s essential to consider both their benefits and potential risks. Overusing or misusing them can lead to the so-called “Antioxidant Paradox,” a situation in which antioxidants may actually cause more oxidative damage rather than preventing it.

This review offers a clear and concise examination of oxidative stress, various types of antioxidants, and their respective strengths and limitations.

Oxidative Stress and Impact

Definition

• Oxidative stress is a condition resulting from an imbalance between the production of free radicals, i.e. reactive oxygen/nitrogen species (ROS/RNS), and the antioxidant defences available within the cells.
• While ROS and RNS play a crucial role in normal cellular functions and the host’s defence mechanisms, their overproduction can lead to the development and worsening of several diseases.

• This figure shows a seesaw-style balance between free radicals (red circle) and antioxidants (blue circle), with the pivot labelled “oxidative stress.”
• 🔎 Meaning:
  • When antioxidants are sufficient, they can neutralise excess free radicals, restoring balance and reducing oxidative stress.
  • When the balance tilts toward free radicals, oxidative stress increases, leading to cellular damage and an elevated risk of disease.

Causes of Oxidative Stress

Infographic Showing Causes of Oxidative Stress

• Factors that elevate the levels of free radicals in the body beyond healthy limits can result in oxidative stress.
• Common examples include:
  • 🍔 Unhealthy eating habits
  • 🚬 Smoking
  • 🍷 Excessive alcohol consumption
  • 🛋️ Sedentary or inactive lifestyle
  • ☠️ Exposure to chemicals and toxins (Pesticides, Heavy Metals, Food Additives)
  • 🌫️ Environmental pollution
  • 🌞 Exposure to ultraviolet radiation (Sunlight and other forms of Radiation)

Harmful Effects of Oxidative Stress

• Oxidative stress contributes to over 100 diseases and plays a role in both initiation and progression of disorders, including:
  • 🩸 Diabetes
  • ⚖️ Obesity
  • 🧠 Neurological disorders (Alzheimer’s disease, Parkinson’s disease)
  • ❤️ Cardiovascular / Heart diseases
  • 🩺 Hypertension
  • 🧴 Skin disorders
  • 🌬️ Respiratory disorders
  • 🍷 Liver diseases
  • 🎗️ Cancer
  • ⏳ Accelerated aging

Understanding Antioxidants

Definition

• Antioxidants are natural or synthetic compounds that help protect your body by reducing oxidative stress, either directly or indirectly.
• They work by neutralising harmful free radicals, which can damage cells and contribute to aging and diseases.
• You can find antioxidants in many common foods such as fruits, vegetables, nuts, and whole grains. Think of them as little shields that help keep our bodies balanced and healthy.

Antioxidants Classification

image illustrates the classification of Antioxidants

• Endogenous (produced in the body):
  • Enzymatic: Superoxide dismutase (SOD), Catalase, Glutathione peroxidase
  • Non-enzymatic: Glutathione, Uric acid, Coenzyme Q10, Alpha-lipoic acid
• Exogenous (Obtained through dietary sources):
  • Vitamins: C, E, A
  • Minerals: Selenium, Zinc, Copper, Manganese
  • Phytochemicals: Flavonoids (quercetin, anthocyanins), Carotenoids (beta-carotene, lycopene, lutein), Polyphenols (curcumin, resveratrol), Sulforaphane

• Widely used in food, packaging, cosmetics, and pharmaceuticals to prevent rancidity and spoilage.
• Examples
  • Butylated Hydroxyanisole (BHA)
  • Butylated Hydroxytoluene (BHT)
  • Propyl Gallate (PG)

Dietary Sources of Antioxidants

• Eating a variety of colourful fruits, vegetables, whole grains, legumes, nuts, seeds, herbs, and spices not only adds vibrant flavours to your meals but also provides a wide range of antioxidants that support your overall health.
• The table below illustrates several key foods rich in antioxidants.

Health Effects of Antioxidants

Potential Role

• Antioxidants are investigated for their role in preventing or managing:
  • Cancer, cardiovascular disease, and aging-related eye disorders
  • Neurological and psychiatric conditions (Alzheimer’s, Depression, Schizophrenia).
  • Inflammatory and metabolic diseases (Diabetes, Rheumatoid arthritis, Obesity).
  • Male infertility and kidney stones.
  • Critical illness and oxidative damage in Dialysis and Stroke patients.

Clinical Facts

• Cancer
  • There is no evidence to support the use of antioxidant supplements in cancer prevention.
  • Beta-carotene supplements may increase lung cancer risk in smokers and asbestos-exposed individuals.
• Cardiovascular disease
  • The U.S. Preventive Services Task Force (2022) advises against vitamin E and beta-carotene supplementation for cardiovascular prevention.
• Age-related macular degeneration (AMD)
  • Antioxidants do not prevent the onset of AMD
  • specific formulations containing antioxidants and zinc can slow its progression.
• Athletes
  • In the long term, high-dose supplementation may blunt the exercise-induced physiological benefits.
• Drug Interactions
  • Antioxidants (vitamins C, E, selenium, beta-carotene) may interfere with chemotherapy, radiotherapy, anticoagulants (blood thinners), and cholesterol-lowering agents.

Claims vs Facts

Key Takeaway

✅ Rely on a balanced diet—not supplements—as the primary source of antioxidants.
✅ Emphasize whole foods for added antioxidant effects.
✅ Avoid high-dose, long-term supplementation due to insufficient evidence and potential harm.
✅ Consult healthcare professionals before combining antioxidants with medications.
✅ Recognise the antioxidant paradox: excessive intake can promote rather than prevent.

Further Reading

• Kotha, R. R., Venkateswararao, A., & Koya, S. (2022). Oxidative Stress and Antioxidants — A Critical Review on Inflammation, Free Radical Damage, and the Role of Antioxidants.https://pmc.ncbi.nlm.nih.gov/articles/PMC9774584/#sec1-antioxidants-11-02388
• Sharifi-Rad, M., et al. (2020). Lifestyle, Oxidative Stress, and Antioxidants: Back and Forth in the Pathophysiology of Chronic Diseases. Frontiers in physiology, 11, 694.https://pmc.ncbi.nlm.nih.gov/articles/PMC7347016/#abstract1
• Pizzino, G., et al. (2017). Oxidative stress: The Harms and Benefits to Human Health. Oxidative Medicine and Cellular Longevity, 2017, 8416763.https://pmc.ncbi.nlm.nih.gov/articles/PMC5551541/#sec4.
• Reddy V. P. (2023). Oxidative Stress in Health and Disease. Biomedicines, 11(11), 2925.https://pmc.ncbi.nlm.nih.gov/articles/PMC10669448/#sec1-biomedicines-11-02925
• Stone WL, Pham T, Mohiuddin SS. Biochemistry, Antioxidants. [Updated 2023 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-.https://www.ncbi.nlm.nih.gov/books/NBK541064
• Kotha, R. R., et Al. (2022). Oxidative stress and antioxidants — A critical review on inflammation, free radical damage, and the role of antioxidants. Antioxidants, 11(12), 2388.https://www.mdpi.com/2076-3921/11/12/2388#
• Sindhi, V., et al. (2013). Potential applications of antioxidants ‒ A review. Journal of Pharmacy Research, 7(12), 828–835.https://www.sciencedirect.com/science/article/pii/S0974694313003733
• National Center for Complementary and Integrative Health. (2022). Antioxidant supplements: What you need to know. U.S. Department of Health and Human Services. https://www.nccih.nih.gov/health/antioxidant-supplements-what-you-need-to-know
• Omaye, S., & Elsayed, N. (2012). Antioxidants to Supplement or Not to Supplement That Is the Question. Antioxidants (Basel, Switzerland), 1(1), 1–3.https://pmc.ncbi.nlm.nih.gov/articles/PMC4665397
• Gallicchio, L., et al. (2008). Carotenoids and the risk of developing lung cancer: A systematic review. The American Journal of Clinical Nutrition, 88(2), 372-383.https://www.sciencedirect.com/science/article/pii/S0002916523240915#ab0005
• Li, S., Fasipe, B., & Laher, I. (2022). Potential harms of supplementation with high doses of antioxidants in athletes. Antioxidants, 11(7), 1406.https://www.sciencedirect.com/science/article/pii/S1728869X22000351#sec5
• Gottlieb S. (2001). Antioxidant vitamins make lipid-lowering drugs less effective. BMJ : British Medical Journal, 323(7325), 1323.https://pmc.ncbi.nlm.nih.gov/articles/PMC1173059/#

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