FOOD, FACTS and FADS

Exploring the sense and nonsense of food and health


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Does the Mediterranean Diet Work? An Update

A previous post described the general results from the PREDIMED Study, a study that reported on the healthy benefits of a Mediterranean-type diet. See the previous post HERE. Now new results from a subset of volunteers from the same study gives us further insight into the way the Mediterranean diet may be heart healthy.

Researchers randomly chose 296 volunteers with a high risk of heart disease who had previously participated the PREDIMED STUDY. Each was assigned to one of the following three diets for one year:

  • A traditional Mediterranean diet with added 4 tablespoons of virgin olive oil per day
  • A traditional Mediterranean diet with an added handful of nuts per day
  • A healthy control that basically was a low fat diet (decreased red meat, sweets, processed food and high-fat dairy products)

Blood tests to measure high density lipoproteins (HDL) and low density lipoprotein (LDL) were conducted at the beginning and end of the study. For a more detailed discussion of the role of HDL and LDL as heart disease risks, see the information at the end of this post.

High levels of LDL or “bad” are linked to an increased risk of plaque formation in coronary arteries while high levels of HDL are linked to a decreased risk. LDL promotes atherosclerosis in arteries and HDL absorbs cholesterol and returns it to the liver for removal from the body. Therefore, its role helps to keep the blood vessels open.

Researchers think that it is not just the number of HDL particles that allegedly reduces the risk of heart disease, but its functional ability to do so, i e., how well does HDL work?

The results of this study showed only the control diet lowered total and LDL cholesterol as found in other studies. None of the diets improved HDL levels significantly; however, the Mediterranean diets both improved the functionality of the HDL significantly. Additionally, this benefit was much larger among those who given the diet with the extra amount of olive oil.

The Med Diets enhanced the functional ability of HDL by:

  • HDL removal of cholesterol from plaque in the arteries
  • Protected the process from LDL action on plaque development
  • Increased blood vessel relaxation to open blood flow.

One author concluded: “Following a Mediterranean diet rich in virgin olive oil could protect our cardiovascular health in several ways, including making our “good” cholesterol work in a more complete way.” The study was published in Circulation 135:633-643, 2017, a journal of the American Heart Association

Risk Factors for Heart Disease include:  High blood pressure, diabetes, obesity, and abnormal blood lipid levels as well as genetics, smoking activity, gender and age.  Some of these risk factors are modifiable by diet.

How are Lipids Transported in the Body?

The liver is the major lipid-producing organ. The liver uses excess protein and carbohydrate to make triglycerides or cholesterol. Triglycerides and cholesterol are carried to the cells by low-density lipoproteins (LDLs), the primary cholesterol delivery system for cells.

LDL’a must be taken up by cells by binding to an LDL receptor on the cell membrane surface or membrane. This binding allows LDLs to be removed from the blood and enter cells where they are broken apart to releases fats and cholesterol for the cell to use. If the amount of LDL cholesterol in the blood exceeds the amount that can be taken up by cells due to either too much LDL or too few receptors, the result is a high level of LDL cholesterol and high levels  are associated with an increased risk of heart disease

How is Cholesterol Eliminated?

Cholesterol cannot be broken down by the body so it must be returned to the liver to be eliminated.  This is accomplished by lipoproteins called high-density lipoproteins (HDLs.) HDLs are particles that originate in the intestinal tract and liver and pick up cholesterol and takes it to the liver for disposal if not needed. A high level of HDL decreases the risk of cardiovascular disease.

So the bottom line:

When you have blood work, the doctor may order blood tests that measures your total cholesterol, your LDL and HDL cholesterol to determine your individual risks of having heart disease in the future.

  • Total Cholesterol: Low risk <200; High risk >240
  • LDL Cholesterol: Low risk <100; High risk   >160
  • HDL Cholesterol: Low risk: > 60; High risk <40
  • Triglycerides: Low risk; <150; High risk >200

So you ideally want your LDL-C to be low and your HDL-C values to be as high as possible (more than likely dependent on diet and genetics. So think L means “lousy” and H means “healthy.”

 

 

 

 

 

 

 


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The Mediterranean Diet: Lower Health Care Costs?


The Mediterranean Diet Pyramid

The Mediterranean Diet is one of  the most “researched” diets of all time and has shown to have positive benefits  in respect to heart disease, cognitive health and cancer prevention. The following article is very interesting and presents an additional benefit  of changing the food culture in any country seeking to improve health care costs.

One promising change is to encourage healthy eating habits in  younger populations –  in this case, teenagers. Early nutrition education is of paramount importance for cultural change. This is where prevention of chronic diseases can make a startling difference. FYI: The Global Health Index of 163 countries ranked the U.S. #34. (Bloomberg, March 2017).

CLICK HERE.


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The Mediterranean Diet – Will it Survive?

graph

What can we learn from the diets and lifestyles of the world’s healthiest cultures? Even though the research has been mostly observational, there are lessons to be learned from how they live their lives and what and how they ate in the past and how those times are changing.

Although the Mediterranean diet has been researched and reputed the world over its health benefits, it is now unfortunately in decline in the very countries of its origin. Older adults remember the good days. One says: “My preferred diet is anything that is green. On a recent day, she prepared a meal of her staple mix of zucchini, tomatoes, and other vegetables all tossed in homemade olive oil. Often she describes adding beans and once in a while some meat from her chickens or rabbits.” New York Times, 2008

How have recent changes from their traditional ways of living affected their once coveted low disease rates of heart disease, cancer, obesity or diabetes?  First take a look at the graph above. It represents cancer incidence rates in both men and women from the major countries of the Mediterranean region when compared to the United States. These rates reflected the traditional diets of the selected countries. Time will tell whether their low disease rates will continue or begin to emulate those of the United States.

The Mediterranean Diet – Then

The traditional diet is plant-based in nature, with a heavy emphasis on fruits and vegetables, nuts, grains, seeds, beans and olive oil. Eggs, dairy, poultry and fish are consumed regularly, but the portions are smaller than typically consumed in a Western diet. Red meat makes only an occasional appearance, and it is usually added in small amounts to make sauces, beans and pasta dishes more flavorful. Refined sugar, flour, butter, and fats other than olive oil are consumed rarely, if at all. Mediterranean eating also typically includes moderate consumption of red wine. One of the key components of Mediterranean eating has to do with the presentation of the meal as a social event. Meals are consumed at leisure with family and friends. This dietary pattern more recently is based on the foods consumed in the 1960’s in the Greek Island of Crete and in southern Italy. At that time, rates of chronic disease were among the lowest in the world and life expectancy was among the highest.

The Mediterranean Diet – Now

What has changed? One thing is that small towns in Crete are now abundant with chocolate shops, pizza places, ice cream parlors, soda machines, and fast-food restaurants.

Greece, Italy, Spain, Portugal, Cyprus and Malta upped their calorie count by 30 percent. As a result, this made Greece the EU country with the highest average Body Mass Index and the highest prevalence of overweight and obesity. In other words, three-quarters of the Greek population are overweight or obese. The rates of overweight 12-year- old boys rose more than 200 percent from 1982 to 2002. In addition more than half of the Italian, Spanish and Portuguese populations are overweight also.

A resident of Rome says it this way when asked if he thinks the Mediterranean diet is on its way out: “I think it is possible — everything is changing so fast- everyone is eating on the run. No one can be bothered anymore; people don’t have the time or want to dedicate the time. Everything is pre-cooked, frozen, and just zapped in the microwave.” Sound familiar? Others say ” it is so hard to get their kids to eat the old ways. They complain about the food companies and fast-food ads that entice children by the prizes offered. Our kids just end up eating mostly pasta, chips and meat..” Children are now tested in elementary school in Crete and a one quarter of all children was found to have high cholesterol. It is not uncommon for doctors to see children with diabetes and high blood pressure. New York Times, 2008.

As one parent complained: “We’re trying to keep her off sugar. If we continue like this, we are going to become like Americans, and no one wants that.” That pretty much sums it up. Time will tell whether that will happen or will they return to their traditional healthy ways.

 

 

 

 

 

 


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The Mediterranean Diet and Aging

Telomere

Telomere (Photo credit: Wikipedia)

By Sally J. Feltner

The purpose of the study was to determine if adherence to a Mediterranean diet could maintain a longer telomere length, a biomarker of aging.Telomeres (DNA sequences) occur at the ends of chromosomes that often undergo a reduction of length each time a body cell divides. Their purpose is to prevent DNA loss to protect the cell’s integrity. Telomere length is proposed to be associated with life expectancy; i.e., shorter length suggests a shorter life and increased rate of developing chronic diseases as we age. The length of telomeres is variable and can be modified by many factors, but generally decreases with age. Since they can be modified, lifestyle factors such as diet may have some effect on the length. On the other hand, telomere length can be restored and elongated during each cell division cycle by an enzyme called telomerase which is also variable. The gene expresssion of this enzyme may also be modified by extrinsic factors.

This study involved 4676 healthy middle-aged women as a subset within the Nurses’ Health Study. They completed food frequency questionnaires and had blood drawn for telomere length analysis. The main outcome measure was to detect an association between telomere length in leukocytes (white blood cells) and self-reported adherence to the Mediterranean diet using a scoring system of the diet called Alternative Mediterranean Diet score.

The Mediterranean diet components primarily include a high intake of fruits, vegetables, nuts, legumes and whole grains along with a high intake of olive oil. It is also associated with a low intake of saturated fat in meats and dairy foods, a moderately high intake of fish and alcohol (especially wine with meals).

A positive adherence to this dietary pattern has consistently shown that there is less risk to develop chronic diseases such as heart disease, dementia, or accelerated aging.

The study also compared the Med diet to other dietary patterns such as the prudent diet (basically a low fat diet) and a so-called Western diet (e.g. the standard American diet) for their effects on leukocyte telomere length.

RESULTS:

Greater adherence to the Mediterranean Diet was associated with a weak positive association with longer telomeres (p=0.02). The difference in telomere length for each one point change in the Alternative Mediterranean Diet score was calculated to be on average 1.5 years of aging. A three point change corresponded to an on average 4.5 years of aging. This is similar to findings when non-smokers are compared to smokers (4.6 years). These results were reported after adjustment for potential co-founders. The results showed no significant positive associations for the prudent diet (p=0.09) or Western diet (p=0.32) patterns and telomere length.

There have been other studies that associated other dietary factors with telomere length. You can read these results in a previous POST.

Strengths of the study:

  • Large population size
  • Detailed dietary records using a validated food frequency questionnaire and dietary score

Limitations of the study:

  • It is not yet been established that telomere shortening is predictive of life expectancy and aging, so this association should be verified.
  • The Nurses’ Health Study results cannot be generalized to other populations, since this group of women was predominantly of European ancestry.
  • The data from food frequency questionnaires was self-reported.

This study was one of the first to  suggest that telomere length variability may be partially explained by lifestyle factors. Oxidative stress and inflammation reduction may have been involved since there is evidence to support that these conditions may accelerate telomere shortening. Again, this was just one study, so a great deal more research is needed.

Source: BMJ 2014; Mediterranean diet and telomere length in Nurses’ Health Study: population based cohort study, 349:g6674