Can Eating One Avocado a Day Help Lower "Bad" Cholesterol?

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I was reading through the interwebs, and something quickly caught my eye - A study about how eating avocados daily can help lower "bad" cholesterol.This is good because I love eating avocado-based food, like guacamole - I always add a bunch to burritos at Qdoba and have substituted it for mayonnaise on my sandwiches. (YUM BTW).

I was always told the little proverb: "An apple a day will keep the doctor away," as I am sure has everyone else! But maybe it should be changed to: "An avocado a day will keep heart disease away."

However, with all of the misinformation out there, I never take a headline as is, so I decided to dig into it before I wrote a blog post about it. Also, you shouldn't just take what I say at will - even though I try to only put top quality information out to my readers, but I'll link to the study so you can get your information from the source!

What is "Bad Cholesterol"?

Bad cholesterol refers to Low-density Lipoprotein or (LDL), whereas "good" cholesterol refers to High-density Lipoprotein (HDL).

Low-density Lipoprotein (LDL) can come in a small/dense form, which can become even more harmful to your body by being damaged by free radicals.

This is known as Oxidised Low-density Lipoprotein. Free radicals are extremely dangerous to our bodies on their own, which is why antioxidants are essential to consume a large amount of daily.

Click here to learn everything about free radicals and oxidation (and how it basically burns you away!)

Small/Dense Low-Density Lipoprotein SD-LDL

SD-LDL is much more succeptable to oxidation by free radical than the larger partical variant because of it's small size. Small LDL particles are particularly atherogenic since they penetrate the vessel wall more easily than larger LDL particles (1)

Atherogenic:

tending to promote the formation of fatty plaques in the arteries

In addition, small and dense LDL is much more likely to stay in your body as studies have shown that they bind to intimal proteoglycans in vitro (2) Which means that in a lab these SD-LDL has been shown to bind to your body tissue in between the cells (proteoglycans).

Avocado study at-a-glance:

Objective - We investigated whether a healthy diet with 1 avocado daily decreased the following secondary outcomes: circulating oxidized LDL (oxLDL) and related oxidative stress markers.

Study Methods:

• Randomized
• Crossover study (Where each participant gets both treatments, but in a random order)
• Controlled feeding
• 45 Men and Women Total (27 men/18 women)
• 21-70 years of age
• Each were overweight or obese
• BMI's of people in study were 25-35
• 3 Cholesterol lowering diets were provided to each participant, each lasting 5 weeks
• Lower Fat Diet 24% calories from fat, 59% carbohydrate, 16% protein
• 7% Saturated Fats, 11% Monounstaurated Fats, 6% Polyunstaurated Fats
• Moderate Fat Diet 34% calories from fat, 49% carbohydrate, 16% protein
• 6% Saturated Fats, 17% Monounstaurated Fats, 9% Polyunstaurated Fats
• High oleic acid oils to mimic the fatty acid profile of one avocado
• Avocado Diet 34% calories from fat, 49% carbohydrate, 16% protein
• 6% Saturated Fats, 17% Monounstaurated Fats, 9% Polyunstaurated Fats
• One hass avocado ~136g per day
• A general linear mixed model was used to analyze the treatment effects
• A 2 week run in on a "normal" American Diet (4% fat, 51% carbohydrate, 16% protein) was provided to participants before the study diets.
• A 2 week break was given between study diets (did not state what their food consisted of during break, presumably the Normal American Diet)

Avocado Study Results:

After all of the participants had tried each of the diets for 5 weeks (with 2 weeks between), it was found that only the avocado diet significantly reduced oxidated LDL. The reduction in the oxidated LDL was primarily due to the reduction in Small/Dense LDL particles.

The avocado diet reduced the oxidated LDL by 8.8% when compared to the Average American Diet. However, this reduction does not seem to be due to the fatty acid composition of an avocado since the Moderate Fat Diet matched the fatty acid profile did not reduce it.

This means that there is something else in an avocado which gives this benefits and not just from healthy fats.

Overall the study shows that avocados can play an important role in reducing small/dense LDL particles in your body, thereby reducing the plaque build up in your arteries (atherogenicity).

This is just another reason to keep adding avocados to your daily diet! But really, who needs a reason to eat an avocado (guacamole)?!