Aerobic exercise and heart-healthy diet may slow development of cognitive impairment without dementia (CIND)

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Cognitive impairment without dementia (CIND), or mild cognitive impairment, is a condition that affects your memory and may put you at risk for Alzheimer’s disease and dementia.

According to the U.S. National Library for Medicine, signs of mild cognitive impairment may include frequently losing things, forgetting to go to events and appointments, and having more trouble coming up with words than other people of your age.

Some experts believe that risk factors for heart disease also are risk factors for dementia and late-life cognitive decline and dementia.

Recently, researchers examined two potential ways to slow the development of CIND based on what we know about preventing heart disease.

They published the results of their study in the Journal of the American Geriatrics Society.

The research team had a theory: That the healthy lifestyle behaviors that slow the development of heart disease could reduce heart disease risk and also slow cognitive decline in older adults with CIND.

These behaviors include regular exercise and a heart-healthy diet, such as the DASH (Dietary Approaches to Stop Hypertension) diet.

In order to investigate their theory, the researchers designed a study titled “Exercise and NutritionaL Interventions for coGnitive and Cardiovascular HealTh EnhaNcement” (or ENLIGHTEN for short).

The goal of the study was to examine the effects of aerobic exercise (sometimes known as “cardio” or “cardiovascular” exercise because it involves activities that increase the circulation of oxygen through the blood) and the DASH diet on cognitive functioning in older adults with CIND.

The ENLIGHTEN study examined 160 adults 55-years-old or older. The study participants were older adults who didn’t exercise and had memory problems, difficulty thinking, and making decisions.

They also had at least one additional risk factor for heart disease, such as high blood pressure (also known as hypertension), high cholesterol, diabetes, or other chronic conditions.

Participants took a number of tests to measure their heart disease risk factors and cognitive ability. Researchers also assessed participants’ dietary habits and ability to perform daily activities.

The participants were then randomly assigned to one of four groups: a group doing aerobic exercise alone, a group following the DASH diet alone, a group doing aerobic exercise and following the DASH diet combined, or a group receiving standard health education.

People in the exercise group did 35 minutes of moderate intensity aerobic exercise (including walking or stationary biking) three times per week for six months.

They were supervised for three months and then exercised unsupervised at home for three months.

Participants in the exercise group did not receive any counseling in the DASH diet and were encouraged to follow their usual diets for six months.

People in the DASH eating plan group received instruction about how to meet DASH guidelines in a series of weekly sessions for three months and then bi-weekly for the remaining three months.

Participants in the DASH group were asked not to engage in regular exercise until the completion of the six-month study.

At the conclusion of the six-month intervention and assessment, participants were free to engage in whatever activity and dietary habits they desired, with no restrictions.

People in the exercise and DASH group followed the exercise and DASH programs for six months.

The participants who were enrolled in the health education group received weekly educational phone calls for three months and then bi-weekly calls for three months.

Phone calls were conducted by a health educator on health topics related to heart disease. Participants were asked to maintain their usual dietary and exercise habits for six months until they were re-evaluated.

At the conclusion of the six-month intervention and assessment, participants were free to engage in whatever activity and dietary habits they desired, with no restrictions.

The results of the research team’s study showed that exercise improved the participants’ ability to think, remember, and make decisions compared to non-exercisers, and that combining exercise with the DASH diet improved the ability to think, remember, and make decisions, compared to people who didn’t exercise or follow the diet–even though they didn’t perfectly follow the programs they were assigned to during the six-month interventions.

The researchers concluded that their findings are promising proof that improved ability to think, remember, and make decisions can last one year after completing a six-month exercise intervention.

They suggested that further studies would be needed to learn more.


A typical modern North American diet is high in saturated fats, omega 6 fatty acids, high glycemic load carbohydrates, and many artificial additives. This unhealthy diet combined with little training in nutrition among the medical professionals is being considered a major setback in tackling these diseases.

Fortunately, there has been tremendous research done in the last few decades examining the effects of dietary patterns on chronic diseases. This information is easily available to physicians online.[4][5][6]

Dietary Approaches to Stop Hypertension (DASH) diet originated in the 1990s. In 1992, the National Institute of Health (NIH) started funding for several research projects to see if specific dietary interventions were useful in treating hypertension. Subjects included in the study were advised to follow just the dietary interventions and not include any other lifestyle modifications, in order to avoid any confounding factors.

They found that just the dietary intervention alone was able to decrease systolic Blood Pressure by about 6 to 11 mm Hg. This effect was seen both in hypertensive as well as normotensive people. Based on these results, in some instances DASH has been advocated as the first line pharmacologic therapy along with lifestyle modification.

What does this diet include? Simply, DASH promotes consumption of vegetables and fruits, lean meat and dairy products and the inclusion of micronutrients in the diet. It also advocates the reduction of sodium in the diet to about 1500 mg/day. DASH emphasizes on consumption of minimally processed and fresh food. DASH diet has many similarities to some of the other dietary patterns which are promoted for cardiovascular health. DASH diet is basically a culmination of the ancient and modern world. It has been derived by scientists based on certain ancient dietary principles and has been tailored to target some of the leading killers of the modern society.

A typical serving guide for a patient following DASH diet is as follows:

  1. Vegetables: about 5 servings per day
  2. Fruits: about 5 servings per day 
  3. Carbohydrates: about 7 servings per day
  4. Low-fat dairy products: about 2 servings per day
  5. Lean meat products: about 2 or fewer servings per day
  6. Nuts and seeds: 2 to 3 times per week

Following is a closer look at these recommendations.

Carbohydrates

Carbohydrates in the diet are mainly composed of cellulose and starches. The human body cannot digest cellulose. It is mainly present in plant fiber. Healthy starches or “carbs” have to be included in the diet, not just for the energy supply but also for the protective micronutrients. Low carb diets are not healthy as that may lead to either decreased caloric intake than recommended or consumption of unhealthy fats as a substitute.

Healthy carbohydrates included under DASH include:

  • Green leafy vegetables: kale, broccoli, spinach, collards, mustards
  • Whole grains: cracked wheat, millets, oats
  • Low glycemic index fruits
  • Legumes and beans

Fats

Fats have been a prime suspect for some time now, in the development of the chronic disease epidemic. However, research has now shown otherwise. Fats are now classified as good fats and bad fats.

Good fats prevent inflammation, provide essential fatty acids and promote overall health. These fats, when consumed in moderation, have shown an increase in HDL and lowering of small dense LDL particles. Some of the sources of good fats also included in DASH include:

  • Olive oil
  • Avocados
  • Nuts
  • Hempseeds
  • Flax seeds
  • Fish rich in omega 3 fatty acids

Bad fats which include margarine, vegetable shortenings, partially hydrogenated vegetable oils, cause increase in small LDL particles, which promote atherogenesis.

Fats are a highly condensed source of energy and therefore have to be consumed in moderation. The serving sizes are much smaller than that for other nutrients on the DASH recommendations.

Proteins 

DASH recommends more servings of plant proteins like legumes, soy products, nuts, and seeds.

Animal protein in the diet should mainly compose of lean meats, low-fat dairy, eggs, and fish.

Processed and cured meats are not recommended as they have shown to cause hypertension and also contain carcinogens.

DASH diet also talks about the inclusion of certain foods which are rich in potassium, calcium, and magnesium as these prevent endothelial dysfunction and promote endothelial, smooth muscle relaxation. Some of the foods rich in potassium include bananas, oranges, and spinach. Calcium is rich in dairy products and green leafy vegetables. Magnesium is present in a variety of whole grains, leafy vegetables, nuts, and seeds.[7][8]

Clinical Significance

Is DASH diet exclusively preferred only for treating HTN?

Since the formulation of DASH diet pattern, it has been studied extensively to look for its effects on multiple other diseases.

Several studies have shown that DASH diet helps lower blood glucose levels, triglycerides, LDL-C, and insulin resistance. This makes DASH diet a very important adjunct to pharmacological therapy in metabolic syndromes, a major epidemic in this country. It also has been a successful tool in weight management. In certain populations, adherence to the DASH diet has shown significant improvements in control of type 2 diabetes. It is a preferred diet in patients with heart failure due to its emphasis on reduction of dietary sodium and encouraging the intake of potassium, magnesium, and calcium.

DASH diet has also shown a reduction in the incidence of colorectal cancer, mainly in the white population. DASH diet has also been proven in multiple studies to have lowered all-cause mortality in adults.

Based on these studies it is safe to say that when combined with pharmacological intervention, DASH can be a very useful tool for physicians to tackle these diseases more efficiently. When compared to some other diet patterns, it has an added advantage of having clear guidelines on the serving sizes and food groups, which makes it easier for the physicians to prescribe and monitor their patient’s improvement.[1][9]

Enhancing Healthcare Team Outcomes

The DASH diet is a nutritionally based approach to prevent and control hypertension. The diet has been tested in several clinical trials and has been shown to lower cholesterol, saturated fats, and blood pressure.

The DASH diet has been recommended as the best diet to help people who would like to lose maintain a healthy weight and lower the blood pressure.

The key fact is that this diet needs to be promoted to patients. Besides physicians, both nurses and pharmacists play a key role in educating patients about the benefits of this diet. Just prior to discharge, nurses are in a prime position to educate all patients and their families about the DASH diet and its benefits. Similarly, when patients visit a pharmacy, the pharmacist should educate the patient about the DASH diet.

The most important feature about the DASH diet is it requires a change in lifestyle and adopt a healthy way to eat. In addition, patients should be urged to stop smoking, abstain from alcohol and do some type of physical activity on a regular basis.[10][11][12] (Level V)

Outcomes

The DASH diet has been well studied in many clinical trials and in most of them has been associated with lowering of blood pressure. Further, there is evidence to show that the DASH diet also lowers the risk of adverse cardiac events, stroke, type 2 diabetes, and obesity. Unfortunately, compliance to the diet remains low. Outside of clinical trials, there are limited studies on the long-term effectiveness of the DASH diet. [13][14] (Level II)


Source:
American Geriatrics Society
Media Contacts:
Daniel E. Trucil – American Geriatrics Society

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