Harvard researchers recommend a spoonful of olive oil daily: What it does in the body.

A tablespoon of olive oil a day can be quite healthy. Studies from Harvard and other institutions show that moderate consumption could reduce the risk of death and protect against dementia.

In the world of nutrition, some statements have become almost commonplace – for example, that olive oil contributes to heart health. But how much is truly beneficial, and what do current studies say? An analysis by researchers at Harvard University suggests that even half a tablespoon of olive oil per day (about 7 grams) may be associated with a lower risk of dementia-related deaths and a longer life expectancy. You can learn about the underlying mechanisms and limitations here.

What do the studies say?

According to a Harvard study that incorporated data from over 92,000 participants in the Nurses' Health Study and the Health Professionals Follow-Up Study, consuming more than 7 grams of olive oil per day was associated with a 28 percent lower risk of dementia-related deaths – regardless of overall diet quality. 

Another study spanning 28 years showed that people who consumed more than half a tablespoon of olive oil per day had a 19% lower risk of overall death than those who used little or no olive oil. The reductions were particularly pronounced in cardiovascular disease, cancer, and neurodegenerative diseases.

Furthermore, data suggest that replacing other fats – such as butter, margarine or mayonnaise – with olive oil can further reduce mortality: Replacing 10 grams of these fats with olive oil was associated with an 8-34% lower mortality rate.

Why olive oil in particular? Possible mechanisms.

• Monounsaturated fatty acids: Olive oil is rich in monounsaturated fatty acids, which can lower "bad" LDL cholesterol without negatively affecting "good" HDL cholesterol – especially with regular consumption over a longer period of time.
• Antioxidants and polyphenols: Extra virgin olive oil contains phenolic compounds such as oleocanthal, which have anti-inflammatory effects and can limit oxidative cell damage.
• Anti-inflammatory and vascular protection: Olive oil can positively influence inflammatory processes, endothelial function, and insulin sensitivity, thereby reducing the risk of cardiovascular disease.
• Cognitive health: Studies show links between olive oil consumption and a lower risk of dementia or declining brain function – correlations that suggest possible positive effects, but do not prove definitive causality.

What are the arguments against a daily dose of oil? Limits & criticism

Even though the study results appear promising, there are some important limitations. First, the available research is predominantly observational. This means that while it shows correlations, it doesn't allow for definitive conclusions about cause and effect. Furthermore, the actual benefit depends heavily on previous fat consumption: those who already primarily use healthy vegetable oils will likely benefit less than someone who previously consumed mainly saturated fats. Another point to consider is the calorie content – ​​olive oil is high in energy, and excessive consumption can quickly disrupt the energy balance and thus promote weight gain. In addition, studies often fail to differentiate between the quality and purity of the oil used. These differences, however, can influence the bioactive substances it contains and therefore its health effects.

Not a miracle cure, but some advantages

A small spoonful of olive oil a day isn't a miracle cure, but it can be part of a healthy diet— especially when it replaces unhealthy fats and is incorporated into an overall balanced eating pattern. Observational studies suggest potential benefits for life expectancy and brain health. However, whether a daily spoonful is beneficial depends on your individual circumstances: your current fat intake, your weight, and your general health.

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