Cooking oils are a pantry staple, but the wrong oils can do more harm than good. Poor-quality oils often introduce oxidative stress and toxins into the body, affecting cellular function and overall health. If you’re shopping at Costco, here’s a guide to understanding which oils are worth buying and which ones you should avoid

Marianne’s Avocado Oil: A Decent Choice

Avocado oil is popular for its versatility and high smoke point, making it a go-to for sautéing, frying, and baking. Costco’s Marianne’s Avocado Oil contains only one ingredient—100% avocados—a positive quality indicator. However, it’s not organic, meaning there’s potential for pesticide exposure.

The oil is packaged in a BPA-free plastic bottle, but BPA-free doesn’t mean toxin-free. Plastics can leach other harmful chemicals when exposed to heat or light, disrupting hormones and increasing inflammation over time.

Marianne’s Avocado Oil is still a better choice than industrial seed oils like canola or corn oil. These oils are often refined using high heat and chemical solvents, making them highly inflammatory. While not perfect, this avocado oil is a reasonable compromise for cooking at high temperatures.

Kirkland’s Signature Olive Oil: A Poor Option

Olive oil has long been celebrated for its health benefits, but Kirkland’s Signature Olive Oil doesn’t live up to the hype. This product is a blend of refined olive oils and just 15% extra virgin olive oil, with no transparency about the sourcing or processing.

For olive oil to provide health benefits, it must be 100% pure, extra virgin, cold-pressed, and ideally organic. Refined blends like this lack the antioxidants and healthy fats that make olive oil a superior choice. Additionally, its packaging in plastic bottles further compromises the oil’s quality, as plastic can contribute to oxidation and leach chemicals into the oil over time.

Kirkland’s Organic Olive Oil: A Better Alternative

Kirkland’s Organic Olive Oil is a much better option for those committed to cleaner eating. Certified organic and traceable to Mediterranean sources, this oil offers higher quality and purity. While it’s still packaged in plastic, its organic certification ensures fewer pesticide residues and a cleaner overall product.

This is a healthier choice for those looking to cook with olive oil, but it’s still best to store oils in cool, dark places to preserve their integrity.

Why Cooking Oils Matter for Your Health

The oils you choose directly impact your body at the cellular level. Poor-quality oils, especially industrial seed oils, are prone to oxidation, leading to free radical damage and inflammation. Over time, this can compromise cellular membranes, disrupt metabolic function, and contribute to chronic disease.

Opting for high-quality oils like 100% pure avocado oil or organic, traceable olive oil helps reduce these risks. While Costco’s options may not be perfect, selecting better oils is a practical step toward supporting your cellular health.

Final Takeaway

When shopping for cooking oils at Costco, weighing the pros and cons is essential. Marianne’s Avocado Oil and Kirkland’s Organic Olive Oil offer cleaner options, but their plastic packaging is a downside. Avoid refined blends like Kirkland’s Signature Olive Oil altogether.

By making more informed choices, you can protect your health and ensure the oils you use in your kitchen are nourishing, not harmful. Always prioritize simplicity, purity, and proper packaging for the best results.