Avocado consumption

Fear of Fats

I remember reading some years ago that avocados should be eaten in moderation because of their high fat content.

That advice makes perfect sense for anyone who has bought into the absurd mindset that any dietary fat is an enemy of good health. As most HSI members are probably aware by now, certain dietary fats are an essential component of good nutrition, a fact that’s highlighted by a study that shows just how misguided it would be to avoid eating avocados because of their fat content.

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Fat vs. fat-free
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In the e-Alert “Silent Partners” (8/5/04), I told you about a study that compared low-fat and fat-free salad dressings to a dressing that contained a normal amount of fat. Blood samples were taken before and after subjects ate salads with the different dressings. Researchers analyzed the samples with an electrochemical technique called high performance liquid chromatography (HPLC) to determine changes in levels of alpha-carotene, beta-carotene and lycopene.

After eating the salad with fat-free dressing, blood tests showed negligible levels of alpha-carotene, beta-carotene, and lycopene in all subjects. These levels were higher after subjects ate the salad with the low-fat dressing. And I’ll let the authors of the study describe the results of the third category: “A substantially greater absorption of carotenoids was observed when salads were consumed with full-fat than with reduced-fat salad dressing.”

That study was conducted by researchers from Iowa State University and Ohio State University. And while that study was impressive, I was even more impressed by a follow up study conducted by the Ohio State team alone.

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Absorbing issues
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The Ohio team set out to determine if avocado consumption improves the absorption of lycopene, lutein, alpha-carotene and beta-carotene.

The study was divided into two parts, and each part had two phases. In the first part, a group of six males and five females ate 300 grams of tomato salsa. About half of the group was given salsa that contained 150 grams of avocado (about five tablespoons), and the others ate salsa without avocado. After a washout period, the test was repeated with the subjects crossing over; those who ate avocado salsa in the first phase were served plain salsa, and vice versa. This first part of the study was designed to determine lycopene absorption.

The second part of the study was designed to determine lutein and carotene absorption. In this part, the subjects ate a salad of carrots, spinach and lettuce. For half the group, salads also contained the 150 grams of avocado. As in the first part, the groups crossed over after a washout period. During both parts of the study, the only fat source was avocado.

Blood was drawn from each subject several times after each meal to determine changes in nutrient levels for up to nine and a half hours after the meals. As in the earlier study, blood was analyzed using HPLC.
The results:

  • Subjects who ate avocado with salsa absorbed nearly 4.5 times more lycopene than those who didn’t eat avocado
  • Subjects who ate avocado with salad absorbed 8.3 times more alpha-carotene and 13.6 times more beta-carotene than those who didn’t eat avocado
  • More than four times as much lutein was absorbed by subjects who ate avocado with salad compared to those who ate only salad

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It’s all good
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In many e-Alerts I’ve told you about the health benefits associated with the nutrients examined in the Ohio State study.

Lutein has been shown to support good vision and helps prevent age related macular degeneration. Good sources of lutein include spinach, eggs, broccoli, carrots, tomatoes, oranges, lettuce and celery.

Many fruits and vegetables are abundant in the two carotenoids, which play a role in the prevention of cancer, heart disease and high blood pressure. And lycopene (found mostly in tomatoes and watermelon) is a powerful antioxidant that promotes heart health and has been shown to reduce the risk of prostate cancer.

And then there’s the avocado, a truly nutrient-dense food that contains:

  • Magnesium
  • Folate
  • Potassium
  • Vitamins B, E and K
  • Glutathione
  • Lutein
  • Monounsaturated fats
  • Omega-3 fatty acids

For some time now there’s been a lot of speculation about why the Mediterranean diet tends to support heart health and prevent cancer. It could be the olive oil; it could be the abundance of fresh, uncontaminated fruits and vegetables; it could be the wine; it could be a combination of all those things or it could be the avocado.

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and another thing

“I thought this was about rowing boats when I saw the headline”

That’s the note that a friend of mine included when he e-mailed a BBC item with this headline: “Marital Rowing Good for Wives.”

In the UK, of course, there’s the kind of rowing that calls for a paddle and a boat, and then there’s the kind of rowing that simply calls for two or more people to have a heated disagreement. And I suppose that those disagreements sometimes involve a paddle if the flare up occurs in a rowboat.

Hopefully you don’t experience many arguments that result in someone swinging a paddle in anger, but according to a recent study presented at the Second International Conference on Women, Heart Disease and Stroke, women who are willing to speak their minds in disagreements with their husbands tend to have healthier hearts. (So mine must be among the healthiest there is.)

Researchers examined 10 years of health records for more than 3,600 male and female subjects who took part in the Framingham Offspring Study. Researchers report that female subjects who were “self-silencing” when conflicts arose were four times more likely to die from all causes compared to women who felt comfortable standing their ground and “rowing.”

Elaine Eaker, the lead researcher for the study, told HealthDayNews that when women self-silence they may activate hormones that take their toll on health over time.

Men in the study who self-silenced didn’t experience health problems that the self-silencing women did. But men married to women who were stressed at home due to pressures at work had a significantly higher risk of heart disease.

Another study reported by the same research team last spring, showed that men who have sudden flare ups of extreme anger have a higher risk of stroke.

Ms. Eaker noted that doctors should ask patients about their stress levels and be alert for signs of chronic marital tension.

To Your Good Health,

Jenny Thompson
Health Sciences Institute

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Sources:

“Avocado Increases the Bioavailability of Carotenoids from Test Meals in Humans” Presented at the 2004 Institute of Food Technologies Annual Meeting, July 12-16, Las Vegas, NV, ift.confex.com

“Avocados May Ward Off Cancer” Newstream, 8/2/04, ktvotv3.com

“Carotenoid Bioavailability is Higher from Salads Ingested with Full-Fat than with Fat-Reduced Salad Dressings as Measured with Electrochemical Detection” American Journal of Clinical Nutrition, Vol. 80, No. 2, August 2004, ncbi.nlm.nih.gov

“Marital Rowing Good for Wives” BBC News, 2/18/05, news.bbc.co.uk

“Avoiding Conflict? It May be Risky” HealthDayNews, 2/18/05, health24.com