Does a High Fat Diet Promote Memory Loss and Cognitive Decline?

A new study out this week and published in iScience found that fat cells play a major role in advancing brain aging and cognitive decline through Na,K+ATPase signaling.  Recent studies have suggested that this pathway is also responsible for conditions that accelerate cardiovascular disease risk including, metabolic syndrome and fatty liver (nonalcoholic steatohepatitis).

The new study was conducted in mice that were genetically modified to release the peptide, NaKtide, in fat cells.  NaKtide is a direct inhibitor of Na,K+ATPase signaling.  The authors found that compared to a control diet, a Western diet (greater than 40% of calories derived from fat) resulted in Na,K+ATPase -mediated cellular inflammation and altered levels of brain biomarkers that affect memory and cognition. These proinflammatory effects were abolished when NaKtide was activated, thereby resulting in improved function of regions that include the brain’s memory center (hippocampus).

The bottom line is that in a mouse model, Na,K+ATPase signaling in fat cells promotes memory loss and neurodegenerative changes.  They raise the possibility that a similarly operative signaling -pathway in humans might lead to adverse long-term neurologic consequences under certain conditions (such as repeated exposure to a high fat diet).  Finally, they suggest that effective therapies directed against this proinflammatory signaling pathway could offset cognitive decline.

Of course, the most effective and currently available approach to reduce cognitive decline as related to this pathway would consist of reducing daily intake of highly saturated, processed and deep-fried foods!

Listed below are additional features related to diet, physical activity, obesity and brain health.

1. Obesity promotes inflammation within the brain leading to cognitive decline and progression of neurodegenerative disorders.
2. Significant and rapid weight loss as a consequence of bariatric surgery has been associated with improvements in cognitive function including memory and executive function.
3. Adherence to the Mediterranean diet – high in vegetables, whole grains, fish, and olive oil – correlates with higher cognitive function.
4. Compared to a high fat, Atkins Diet, a low fat Ornish Diet is associated with low levels of TMAO, a gut metabolite predictive of increased cardiovascular disease risk and reduced cognitive function.
5. Replacement of saturated fat by polyunsaturated or monounsaturated fat is associated with lower rates of neurodegenerative disease.
6. Higher levels of physical activity are associated with a 35% reduced risk of cognitive decline and 14% reduced risk of dementia.
7. A diet containing at least one serving of green leafy vegetables each day is associated with slower age-related cognitive decline by approximately 10 years.
8. Metabolic Syndrome is associated with increased risk of developing cognitive impairment and premature dementia.
9. Chronic exposure to stress confers a higher risk of developing neurodegenerative disorders including Alzheimer’s disease.
10. Chronic insomnia is associated with a 30-35% increased risk of progressive dementia.
11. Musicians are 64% less likely to develop mild cognitive impairment or dementia, even after adjusting for physical activity and education.
12. Drinking 3-5 cups of coffee per day at midlife was associated with a decreased risk of dementia and Alzheimer’s Disease by about 65% at late-life.
13. Speaking at least 2 languages has been shown to delay the onset of dementia by 4-5 years.

Dr. Michael Miller is Professor of Cardiovascular Medicine at the University of Maryland School of Medicine in Baltimore, Maryland.  Check him out on twitter: @mmillermd1

Early Onset Hypertension= Early Onset Dementia

 

 

A new study out this week has found that being diagnosed with elevated blood pressure at a young age, is associated with risk of early dementia.

The study published in the American Heart Association journal, Hypertension analyzed 11,399 Chinese adults who were diagnosed with hypertension at 3 age groups: 1)when they were younger than age 35; 2) between ages 35 to 44 and 3) aged 45 to 54 years. Another 11,399 men and women without a history of high blood pressure served as the control group.  Brain MRI scans were performed in all participants. The results of the study indicated that in all 3 comparator age groups, those with hypertension exhibited smaller brain (volume) sizes with the largest difference observed in the group under age 35.

Among the subjects who developed any type of dementia during the study period, the risk was 61% higher in men and women 35-44 years of age who had been diagnosed with hypertension compared to similar aged normotensive controls. In addition, vascular dementia was increased 45-69% when hypertension was diagnosed between ages 35-54 years. To review this paper, click here.

The study supports early identification and treatment of high blood pressure – it stands to reason that control of hypertension at a young age would reduce development of dementia.

High blood pressure can occur under a variety of circumstances and may be associated with the following:

1. Exercise induced hypertension (systolic pressure greater than 210 mmHg in men and 190 mmHg in women with exercise) is associated with a 35-40% increased risk of cardiovascular events and mortality.
2. Hypertension of the eyes (ocular hypertension) raises the risk of glaucoma.  Risk factors for ocular hypertension include diabetes, hypertension, extreme nearsightedness and chronic steroid use.
3. Black licorice can raise blood pressure and cause palpitations when 2 or more ounces are consumed per day.
4. Herbal supplements that may raise blood pressure include ginseng, guarana, ma-huang and St. John’s Wort.
5. Examples of commonly used drugs that may raise blood pressure include NSAIDs (ibuprofen), steroids (prednisone), decongestants (pseudoephedrine), antidepressants (fluoxetine) and anti-infectives (ketoconazole).
6. The 4 “classic H signs” of Pheochromocytoma, Hyperhydrosis (excessive sweating), Hypertension, Heart palpitations and Headache are only observed in 40% of cases.
7. Hypertension with disproportionate pulses (reduced in lower compared to upper extremities) could be due to narrowing of the aorta (coarctation). Coarctation is associated with exercise induced hypertension.
8. Recent onset of high blood pressure associated with kidney stones, bone pain and abdominal pain (also known as “stones, bones and groans”) may be the result of high calcium levels due to an overactive parathyroid gland.
9. Hypertension is observed in up to 70% of those affected with obstructive sleep apnea. Treatment of sleep apnea and its underlying causes, may effectively reduce blood pressure.
10. Up to 30% of patients with hypertension do not respond effectively to 3 blood pressure medications. The most common condition associated with “resistant hypertension” is obstructive sleep apnea.
11. A recently diagnosed elevation in blood pressure that exceeds 150/100 mmHg on 3 different days should be screened for the rare medical condition, primary aldosteronism (Conn’s Syndrome).
12. A young woman with recent onset hypertension in association with tinnitus (ringing in the ears), dizziness, neck pain and poor kidney function may be due to another rare medical condition, fibromuscular dysplasia, recently been linked to spontaneous coronary artery dissection (SCAD).
13. Consider a workup for acromegaly in someone who has recently developed hypertension along with an increase in shoe (and glove) size. Complications of acromegaly include resistant hypertension, diabetes, and an enlarged heart, thereby raising  the risk of arrhythmia (abnormal heart rhythm) and sudden death.

Dr. Michael Miller is Professor of Cardiovascular Medicine at the University of Maryland School of Medicine in Baltimore, Maryland.  Check him out on twitter: @mmillermd1