STORY AT-A-GLANCE

• A TikTok trend suggests drinking a shot of olive oil each day is good for you, but the reality is that it could harm your health

• I recommend limiting olive oil intake to 1 teaspoon a day due to its linoleic acid (LA) content, or better yet, avoid it completely

• Typically, olive oil contains anywhere from 3% to 21% linoleic acid, but it’s commonly adulterated with seed and vegetable oils, which will drive its LA content even higher

• Consuming too much LA is associated with cardiovascular disease, cancer, Alzheimer’s and other chronic diseases

• To find high-quality, pure olive oil, only purchase trusted and tested brands; then, put the oil in your refrigerator, as the LA will remain liquid. Simply pour that oil in your trash and your olive oil will be healthier, since you reduced its LA content

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Have you seen the latest TikTok trend urging people to start their day off with a shot of extra virgin olive oil? This is yet another social media fad you’re better off avoiding. While olive oil is widely regarded as a health food — the TikTok trend suggests drinking olive oil can boost metabolism and improve gut and skin health,1 for instance — it contains linoleic acid (LA).

There’s been a series of mainstream articles touting the Mediterranean diet, specifically praising the health benefits of olive oil. However, contrasting views exist, particularly concerning its link to obesity. Historical skepticism, such as that from Plato, who deemed olive oil harmful, contrasts sharply with its modern accolades.

Intriguingly, areas like Greece, Spain, and Southern Italy, known for high olive oil consumption, also report some of the highest obesity rates in Europe. This has sparked debates about olive oil’s role in health, given its nutritional profile predominantly featuring oleic acid, a monounsaturated fat known for health benefits.

While pure, unadulterated olive oil contains less linoleic acid than other vegetable and seed oils, like safflower, grape seed, corn and soybean oils, it’s often cut with cheaper oils, raising its LA content. This is problematic, as consuming too much LA, as most Americans do, increases your risk of multiple chronic diseases.

Even under the best circumstances, meaning you’ve found a high-quality, unadulterated brand of organic olive oil, I recommend limiting olive oil intake to 1 tablespoon a day due to its LA content. Assuming a typical shot glass holds 1.5 ounces, a daily shot of olive oil would contribute about 3 tablespoons of olive oil to your diet — three times my top recommended limit.

Oleic Acid — Major Problem with Olive Oil

I have previously interviewed Brad Marshall on reductive stress and he has done a magnificent job in highlighting the problems with oleic acid and how it increases the risk of obesity and metabolic dysfunction. Further exploration into the relationship between olive oil and obesity reveals complex dynamics. Despite high local olive oil consumption, studies suggest that its impact on body mass index (BMI) is negligible.

• This challenges the notion that olive oil directly contributes to obesity — However, this narrative took a defensive turn when researchers, rather controversially, attributed obesity rates in Mediterranean regions to lifestyle factors like physical inactivity rather than dietary habits. This perspective was tested in experiments where dietary olive oil was shown to induce insulin resistance in mice, suggesting a potential metabolic concern.

• Animal model studies reveal oleic acid’s isolated effects — In-depth studies have used animal models to isolate the effects of oleic acid, aiming to control variables present in olive oil like polyphenols and saturated fats.

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  Results indicated that pure oleic acid led to even greater insulin resistance in mice, highlighting concerns over its metabolic impacts when isolated from other components typically found in olive oil. This points to the complexity of olive oil’s health impacts, suggesting that beneficial outcomes might be more attributable to its polyphenol content rather than the oil itself.

• Monounsaturated fats and fat metabolism mechanisms — The discourse expanded with studies focusing on how monounsaturated fats influence fat metabolism and storage, particularly through mechanisms involving the desaturase enzymes, which convert saturated fats into monounsaturated fats. These enzymes, upregulated by dietary monounsaturated fats, play a significant role in lipogenesis, the process of converting carbohydrates into fatty acids.

• The complexity of olive oil’s role in metabolic health — This biological pathway is crucial as it not only highlights how dietary fats influence lipid profiles but also underscores the nuanced interplay between different types of dietary fats and metabolic health. While olive oil is celebrated for its health benefits, primarily due to its rich monounsaturated fat content and polyphenols, the broader implications of its consumption are complex.

The potential for olive oil to influence metabolic pathways, particularly in how it may modulate fat synthesis and storage, calls for a balanced perspective on its consumption within a dietary context. These findings invite a more cautious approach to dietary recommendations, suggesting that the integration of olive oil into diets should consider individual metabolic responses and broader dietary patterns.

Why Is Linoleic Acid Harmful?

My peer-reviewed paper on the hazards of linoleic acid, an omega-6 polyunsaturated fat (PUFA), is published in the high-impact nutrition journal Nutrients and can be downloaded for free.2

• Excess linoleic acid produces harmful oxidized metabolites — While LA is an essential fatty acid, when too much is consumed it becomes a precursor to oxidized LA metabolites (OXLAMs), such as 4-Hydroxynonenal (HNE), 9- and 13-hydroxy-octadecadienoic acid (9- and 13-HODE), and 9- and 13-oxo-octadecadienoic acid (9- and 13-HODE), which are associated with cardiovascular disease, cancer, Alzheimer’s and other chronic diseases.

• High linoleic acid intake impairs mitochondria and damages the liver — Excessive levels of LA may also lead to impairments in mitochondrial function, while OXLAMs are toxic to the liver and associated with inflammation, fibrosis and fatty liver disease in humans.3

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  As researchers further noted in the journal Nutrients, “In addition, a few studies suggested that omega-6 PUFA is related to chronic inflammatory diseases such as obesity, nonalcoholic fatty liver disease and cardiovascular disease.”4

• Linoleic acid contributes to oxidation, hypertension, and cancer — Consuming too much linoleic acid is also associated with high blood pressure and cancer, while its autoxidative stability — meaning how resistant it is to oxidation — is 10 times lower than oleic acid5 — the main fatty acid in olive oil. This means oils high in linoleic acid are more prone to going rancid quickly.

Further, because the half-life of LA is about two years, the damage it causes is persistent and may not resolve for years after you’ve dramatically cut back on your LA intake.

How Much Linoleic Acid Is in Olive Oil?

Olive oil consumption has grown considerably in recent decades, nearly doubling from 1990-1991 to 2020-2021.6 Oleic acid is the predominant fatty acid in olive oil, making up 55% to 83% of its total fatty acid content.7 This monounsaturated fatty