Olive Oil Linked to Lower Risk of Death Due to Heart Disease, Cancer, and Alzheimer’s Disease

Could something as simple as using ½ tablespoon (tbsp) or more of olive oil instead butter or full fat dairy in your daily diet help increase your chances of living longer? That would be a yes, according to a new study from the Harvard School of Public Health, published on January 18 in the American Journal of Cardiology.

Researchers found that individuals who used 7 grams (g) or more — around ½ tbsp — in cooking, as a dressing, or along with their bread, had a reduced risk of dying of heart disease, cancer, respiratory disease, or Alzheimer’s disease when compared with people who rarely or never consumed olive oil.

Replacing about 10 g a day (about ¾ tbsp) of butter, margarine, mayo, or dairy fat with the equivalent amount of olive oil was associated with a lower risk of early death as well.

These findings support current dietary recommendations to increase the intake of olive oil and other unsaturated vegetable oils, said lead author Marta Guasch-Ferré, PhD, a senior research scientist in the department of nutrition at Harvard T.H. Chan School of Public Health in Boston, in a release.

"Clinicians should be counseling patients to replace certain fats, such as margarine and butter, with olive oil to improve their health. Our study helps make more specific recommendations that will be easier for patients to understand and hopefully implement into their diets,” said Dr. Guasch-Ferré.

What Are the Health Benefits of Olive Oil?

There are different types of fatty acids in olive oil, but it’s mostly composed of monounsaturated fats. Monosaturated fats can help reduce the amount of low-density lipoprotein (LDL), also known as “bad” cholesterol, which can lower the risk of heart disease and stroke, according to the American Heart Association (AHA).

Olive oil isn’t lower in calories than other types of oil — it contains 9 calories per g (about 120 calories per tbsp), according to the U.S. Department of Agriculture, which is the same other types of fat. That’s why experts recommend substituting olive oil in place of a less healthy oil or butter rather than just adding it to your diet.

People Consume More Olive Oil and Less Margarine Than in Previous Decades

Investigators examined 60,582 healthy women and 31,801 healthy men from the Nurses' Health Study and the Health Professionals Follow-up Study. During the 28-year follow-up, participants had diet assessment every four years that asked them how often, on average, they consumed specific foods, types of fats and oils, as well as which brand or type of oils they used for cooking and added at the table in the previous year.

The participants’ use of olive oil in cooking, dressings, and as a dip for bread were calculated and added together to estimate total use, and the use of other types of fats such as margarine, butter, and vegetable oil were calculated in the same way.

Researchers observed a trend over time: Olive oil consumption in the group more than doubled from 1990 to 2010, from 1.6 g to 4 g. During the same period, margarine use dropped from 12 g a day in 1990 to 4 g a day in 2010. The use of other types of fat remained about the same.

People Who Consume More Olive Oil More Likely to Have Other Healthy Behaviors

Researchers placed each participant into one of four groups, depending on how much olive oil they used.

• Never or less than one time per month
• Less than or equal to 4.5 g (about 1 tsp) per day
• Between 4.5 and 7 g (about 1 tsp to ½ tbsp) per day
• More than 7 g (about ½ tbsp) per day

Interestingly, subjects who consumed more olive oil were more likely to be physically active, of Southern European or Mediterranean ancestry, and a nonsmoker, and reported eating more fruits and vegetables than people who consumed less olive oil.

A total of 36,856 deaths occurred during the follow-up. When comparing the groups, the people who consumed the most olive oil had a 19 percent lower risk of cardiovascular mortality, 17 percent lower risk of cancer mortality, 18 percent lower risk of respiratory mortality, and a 29 percent lower risk of neurodegenerative mortality when compared with the group who rarely or never used olive oil.

Respiratory disease includes acute illnesses such as pneumonia and influenza, as well as chronic conditions such as chronic obstructive pulmonary disease (COPD). Neurodegenerative diseases are when nerve cells in the brain or peripheral nervous system gradually lose function and die, according to the National Institute of Environmental Health Sciences. The most common neurodegenerative diseases are Alzheimer’s disease and Parkinson’s disease.

Investigators also found that substituting 10 g a day of fats such as margarine, butter, mayonnaise, and dairy fat with olive oil was associated with 8 to 34 percent lower risk of total and cause-specific mortality. They found no significant associations when substituting olive oil for other vegetable oils.

Olive Oil and Other Healthy Fats May Help Protect Your Brain

“This study adds to the growing literature on the importance of diet and healthy fats for brain health,” says Suzanne Craft, PhD, professor of medicine and codirector of the Sticht Center for Healthy Aging and Alzheimer’s Prevention at Wake Forest School of Medicine in Winston Salem, North Carolina.

“The brain obtains all of its essential nutrients from the diet, so it is not surprising that dietary patterns that are repeated meal after meal, day after day, year after year, can affect how the brain ages,” says Dr. Craft.

Fats are particularly important because brain cells and their connections contain high levels of fat, which is important for their normal function, she explains. “Unhealthy fats increase inflammation, which has negative effects on the brain and may increase the risk for Alzheimer’s disease and other brain aging disorders, while healthy fats such as olive oil are anti-inflammatory and may be protective as suggested by this study,” she says.

There are a few limitations to the study, says Craft. “The study is observational though, which makes it subject to some biases, and conclusive evidence is needed through interventional trials,” she says, referring to the fact that researchers in this study simply recorded the different fats and amounts that participants reported, rather than randomizing a group and giving people specific instructions about how much and what type of fat they should consume.

The authors acknowledged that olive oil may be associated with other behaviors that would make people less likely to die, such as having a better diet overall, or being in a higher socioeconomic class. “However, even after adjusting for these and other social economic status factors, our results remained largely the same," Guasch-Ferré said.