While it doesn’t take a nutrition degree to know a milkshake is not the healthiest of menu items, a study published today in Laboratory Investigation may offer an even more compelling reason to opt for water instead. According to the findings, a single high-fat item, like the types of milkshakes found in some restaurants, can quickly transform healthy red blood cells into small, spiky cells that wreak havoc in the blood vessels and set the stage for cardiovascular disease. While these changes were temporary in healthy subjects, it is likely that continual, regular consumption of these types of meals take a cumulative toll. These findings could explain isolated reports of death and/or heart attack right after eating a very high-fat meal.
Scientists from the Medical College of Georgia recruited ten physically active men with a good medical history for their study on the effects of fat consumption. They were told to avoid caffeine and strenuous physical activity for 24 hours before testing and to fast overnight. Since estrogen is considered cardioprotective in females, the researchers chose to focus their research on males.
On the day of the test, half the men got a milkshake containing approximately 80 grams of fat and 1,000 calories, while the other half were given low-fat sugary cereal with low-fat milk. The meals varied slightly to ensure everyone got the same amount of fat relative to their body weight.
Four hours following the meal, which is about the time it takes for food to digest, the blood cells of the milkshake group had changed shape and gotten smaller. There was also evidence of myeloperoxidase (MPO), an enzyme expressed by neutrophils, which has been linked to stiff blood vessels, oxidative stress and heart attack when present in high levels in the blood. MPO can also affect the cytoskeleton, causing the spiked appearance observed in the study.
Analysis with flow cytometry revealed an increase in reactive oxygen species as well.
Furthermore, monocytes appeared to get fat while trying to take up the excessive fat. Earlier studies have shown that these ‘foamy’ monocytes promote inflammation and show up in atherosclerotic plaque. Thickening of the plasma following milkshake consumption was also observed.
While excessive calories and sugar are not recommended either, the sugary cereal-eating group did not experience the same harmful changes to their blood, red blood cells and blood vessels.
In mice and human studies, unhealthy changes resolved quickly, after about eight hours if the high-fat meals did not continue. However, in mice continuously fed a high-fat diet, permanent changes to their red blood cells were observed.
While further research is needed to determine precisely how these changes affect individuals long-term, the researchers recommend primary prevention as the best course of action. This includes healthy eating, regular exercise and keeping track of blood pressure and cholesterol levels. Other studies done by the team have indicated a single aerobic exercise session by healthy individuals can counteract the unhealthy slump at four hours.