Does Dairy Deserve Designation as Heart Healthy?

In 1977 an advertising campaign was launched featuring the first American commercials produced in the Soviet Union.  The ads depicted older individuals from Soviet Georgia, several of whom were over 100 years old, eating yogurt.  One scene showed an 89-year-old man eating yogurt. Beside him was his 114-year-old mother who was looking quite pleased with his dietary choice. The obvious implication is that yogurt was responsible for the spectacular longevity in these Georgians. The ads were quite memorable and very successful, launching a little known yogurt company to prominence and starting the yogurt consumption craze in the US.

Dairy products are a good source for essential vitamins (A and B12), minerals (such as calcium and potassium) and high quality protein. On the other hand, dairy products are a leading source of saturated fat, cholesterol and sodium, all of which are detrimental to heart health. The American Heart Association/American College of Cardiology, the DASH (Dietary Approach to Stop Hypertension) Diet and Mediterranean Diet all recommend avoiding full fat dairy products and substituting fat free or low fat sources of dairy. What is the recent data on milk, yogurt and cheese and heart disease?

The PURE study evaluated 136,000 people from 21 countries and five continents.  The study showed that those who consumed 2 or more dairy products (milk, yogurt and cheese) per day had a lower risk for dying and lower risk for cardiovascular death than those who did not eat dairy. Even in those who consumed only high fat dairy, there was a lower risk for dying, which seemingly contradicts all of the previous dietary recommendations. Another large analysis of several dairy trials confirmed these findings concluding that high fat milk did not increase heart disease or mortality.  So it seems that dairy fat may not increase the risk for heart disease and death.  The lesson from theses studies is the importance of evaluating dairy products not just on their fat content, but on their total nutritional value. 

What about yogurt, can it prevent heart disease? One study evaluated 1900 middle-aged men without heart disease and followed them for 20 years. The study found that consuming yogurt cut the risk for heart attack in these men.  It has also been shown that higher intake of yogurt decreases the risk for type 2 diabetes.  In choosing a yogurt, it is important to choose a sugar free or low sugar product as many yogurts have added sugar. 

Next up is cheese. Can eating a small amount of cheese every day benefit heart health?  A major study of 200,000 participants sought to answer this question. The enrollees were monitored for 10 years and most did not have heart disease. The study showed that eating around 1.4 ounces of cheese every day lowered the risk for heart disease, heart deaths and stroke.  However, not all cheeses are equal. For example, feta cheese is a low fat low calorie cheese favored in the Mediterranean diet. One ounce of feta is lower in fat (6 grams) and calories (74) than one ounce of cheddar or parmesan cheese (110 calories and 7 grams of fat).  Skim mozzarella is another low calorie cheese (72).  High calorie cheeses include gouda (101), swiss (111) provolone (98) and brie (95).  

One thing to keep in mind is that the research supplying all of this data is not the strongest.  Many of the studies are observational (they can observe an effect but not prove cause and effect) and many are sponsored by the dairy industry (so bias cannot be excluded). Despite this, a couple of things are clear. One is that eating a yogurt a day will not guarantee that you will live to one hundred. The other is that, in general, dairy is quite healthy. Dairy products provide significant nutritional value and may reduce the risk for cardiovascular disease and dying. It seems prudent to follow the guidelines of the Mediterranean diet and consume two servings of low fat dairy per day. This should come mostly from low fat or fat free milk, low fat yogurt and cheese. Low fat cheese should be limited to 3 servings per week, but choose your cheese carefully!

Can Jellyfish Ward off Dementia?

Hearing the word dementia has a devastating effect on those who have had a family member suffer with it. What is dementia and can it be prevented? Dementia isn’t a specific disease, but an umbrella term for a set of symptoms that affects memory, thinking, personality, and activities of daily living.  In addition, there is confusion, disorientation, and difficulty in finding words and problem solving.  Alzheimer’s disease is the most common cause of dementia, occurring in two thirds of all cases.  Vascular dementia is the second most common type, occurring as a result of damage to the blood supply to the brain. This damage may be from a stroke, diabetes or high blood pressure, putting heart patients at risk.  While dementia is not a normal part of aging, the older we get, the higher the risk for dementia.  Genetics play a big part; those with a family history of dementia are at higher risk. Other risk factors include, heavy alcohol use, smoking, high blood pressure, depression and diabetes. 

Mild cognitive impairment is an intermediate stage, where there are changes in thinking that exceed normal aging (benign forgetfulness), but not as severe as full-blown dementia (malignant forgetfulness).  One passes through the mild cognitive impairment stage on the way to dementia. 

Neither mild cognitive impairment nor dementia can be cured. There are many medications which help with the symptoms, but they don’t alter the course of the disease. Can dementia be prevented?  There are many over the counter products being sold that claim to prevent dementia. These include supplements, vitamins, ginkgo biloba, jellyfish proteins, green tea extract, St John’s wort and others. However, when rigorously tested, none of these compounds have been shown to slow the progression to dementia, despite their advertising claims. In February 2019, the Food and Drug Administration cracked down on the sale of unapproved products claiming to prevent, treat or cure Alzheimer’s disease sending warning letters to 17 companies selling these supplements.  Since this approach doesn’t work, what can prevent dementia? In 2017, a National Academy of Sciences panel reviewed all of the published prevention studies and suggested three interventions to slow cognitive decline: increased physical activity, blood pressure control and being mentally active. 

Controlling high blood pressure as a measure to prevent dementia is an appealing concept.  The brain seems to be very vulnerable to sustained high blood pressure. Hypertension changes the structure of the small blood vessels of the brain, leading to vascular dementia. In addition, hypertension is a well-known risk factor for stroke. Can lowering blood pressure reduce the stress on the blood vessels and delay the progression of dementia? This hypothesis was tested in two large trials. In the HOPE trial, lowering blood pressure did not delay cognitive decline. This trial only included patients older than 70 years old. The SPRINT trial enrolled 9000 hypertensive patients with an average age of 68 and followed them for 5 years.  The risk for dementia was not reduced by intense blood pressure lowering (a blood pressure goal less than120) compared to a blood pressure goal less than 140.  However, the intense treatment group had a lower risk for mild cognitive impairment.  Unfortunately neither trial was able to prove that lowering blood pressure prevented dementia, but there are signals that we may be on the right path.  Both trials may be limited as the patients were older and followed for only a few years. Perhaps patients have to be followed for many years to see an effect and perhaps blood pressure control should start at an earlier age (for example, starting medications when patients are in their 40’s). 

Thousands of studies have been conducted looking at exercise and brain function. In general, exercise is felt to be beneficial.  Exercise may be helpful in a variety of ways including lowering blood pressure and promoting neurogenesis (the generation of new brain cells).  A large recent study evaluated all of the clinical trials on exercise and brain function and concluded the following. Exercise significantly improved cognitive function in adults over 50 years old, even if mild cognitive impairment or dementia were already present. Since some patients may begin to show signs of dementia as early as 45 years old, it is never too early or too late to start exercising.  Aerobic exercise and resistance training were similarly effective. To achieve improvement in cognitive function, exercising for a minimum of 45 minutes at moderate to vigorous intensity, on as many days of the week as possible is recommended.

There is a lot we don’t know about preventing dementia. We do know that taking brain supplements and substances found in jellyfish do not work. Lowering blood pressure may be helpful but even if it isn’t, there is no downside. Controlling blood pressure is always beneficial for overall health and there is little risk. Similarly, exercise may or may not help prevent dementia but it is good for overall health and there are no side effects. So skip the supplements and walk away from dementia.