Mediterranean Diet improves blood pressure in older adults

You may not realize this, but older adults (typically considered to be 65 or over) have specific dietary needs. As the body ages, it becomes more important to maintain bone health to prevent breaks, so Calcium and Vitamin D become even more essential. Some research suggests that greater protein intake may help reduce the sarcopenia (muscle wasting) that's so common in older age, but at the same time it's important to maintain a healthy weight - simply eating more protein-containing foods may contribute to weight gain.

It's also important for older adults to fight higher blood pressure by increasing potassium intake and reducing sodium intake, as higher blood pressure and greater arterial stiffness is a common side effect of greater age.

Arterial stiffness is also known as "hardening of the arteries" or "atherosclerosis" - a condition in which the arteries become narrowed due to cholesterol deposits within the arteries. These deposits in turn contribute to the inside walls of the artery developing fibrous tissue and calcification (called arteriosclerosis). This can eventually block the artery, causing the death of the tissues supplied by the artery.

A team of researchers from across Europe designed a randomized controlled trial to assess the effects of a Mediterranean-style diet specifically tailored for those 65 and over on blood pressures and arterial stiffness (Hypertension 2019;73:578-586). Over 1,100 men and women between the ages of 65 and 79 were recruited from 5 clinics across Europe.

Half of the participants were assigned to a customized Mediterranean-style diet, while the other half continued their usual diet and were provided with information outlining the current dietary guidelines for their area. Both groups filled out 7-day food diaries before the official start of the study to evaluate each participant's baseline diet.

Those in the test group - the customized Mediterranean-style diet - received individualized dietary counseling from dietitians to help them adopt and adhere to a Mediterranean-style diet that was modified to: increase even further the intake of whole grains; increase low-fat protein sources, including dairy, lean meat, and fish, beyond the standard Mediterranean Diet; reduce sodium overall; and include a vitamin D supplement.

To help the test group adhere to their diet, the authors arranged to provide the participants with whole grain pastas, extra virgin olive oil, low-fat and low-sodium cheeses, margarine that was high in polyunsaturated fats (but without trans-fats), and the previously mentioned Vitamin D supplements.

Those test group participants filled out 3-day food diaries and returned any unused Vitamin D supplements at the 4th and 8th months of the trial so the authors could evaluate how well the participants stuck to their diets.

All of the participants had their blood pressures checked at the start and end of the 1-year study. Further, their urine was collected for a 24-hour period, again at the start and end of the study, to test for sodium and potassium excretion (allowing the researchers to estimate sodium and potassium intake).

The authors compared the health experiences of those following the modified Mediterranean-style diet with those who continued with their usual diet. Further, with the detailed dietary questionnaires they were able to assess the impact of specific components of a Mediterranean Diet on the risk of all-cause mortality.

Over the test year those in the control group did not appreciably change their diet, while those in the test group improved their diet significantly, most notably in the areas of increased nuts, legumes, and whole grains, fish, low-fat dairy, and olive oil, while reducing their intake of products high in sugar by over 20%. Neither group appreciably changed their intake of lean meat and poultry or alcohol.

Still, those who were following the modified Mediterranean-style diet reduced their systolic blood pressure (that's the bottom or second number in a blood pressure reading) by almost 5 points, while those continuing on their usual diet lowered their systolic blood pressure by a little less than 1 point. About one-quarter of the participants had their arterial stiffness measured: those on the Mediterranean-style diet improved their arterial stiffness score (becoming less stiff) while those on the control (usual) diet saw their arteries become more stiff by about the same amount.

What this means for you

This randomized controlled trial shows that following a Mediterranean-style diet modified to meet the special dietary needs of those over 65 can indeed improve blood pressures and arterial stiffness. This is great - but the problem we see for patients is that this study provided appropriate foodstuffs to the participants, making it easier (and cheaper) for them to follow the assigned diet. You, dear readers, can make dietary change a bit easier on yourselves by approaching these improvements one at a time: start slowly by using more olive oil in cooking rather than butter, then choose lower fat cheeses rather than full-fat cheeses, cut back on saturated fats by cutting out higher fat animal proteins and choosing leaner meats, and switch your white flour pastas for whole wheat pastas. Ease into these changes and you'll find your meals both tastier and better for you while still being delicious and satisfying.

First posted: March 13, 2019