Long Term Cognition via controlling Blood Sugar

The dangers of high blood sugar:


Higher blood sugar means higher risk of dementia. High blood sugar can result in a high fructose level in the brain.


A good blood sugar level matters as much to healthy people as it does to diabetics. Even for people who don’t have diabetes or high blood sugar, those with higher blood sugar levels are more likely to have memory problems and dementia.


According to Dr. David Hansen, in this video, the biggest culprit leading to Alzheimer’s is excess sugar consumption, which leads to insulin resistance, which damages the brain. Dr. Hansen points out that excessive sugar consumption leads to:

  • insulin resistance
  • inflammation
  • oxidative stress


All of those will impair mitochondrial function. A byproduct of fructose consumption is uric acid, which causes microscopic inflammation and oxidative stress in the brain. Another hazard of fructose consumption is glycation and advanced glycation end products which is what ages you. Fructose also generates 100X the number of oxygen radicals compared with glucose leading to more oxidative stress and sick mitochondria.


Fructose also reduces the functioning of leptin and BDNF.


The systematic review and meta-analysis of 15 studies found that fructose consumption was positively associated with increased fasting blood sugar, elevated triglycerides, and elevated systolic blood pressure.


The fiber in fruits makes them OK for moderate consumption, but not as smoothies. The fiber in fruits tends to blunt blood sugar spikes, but one should not consume fruits to excess, especially fruits with a high GI score.


A diet of unprocessed food increases beta hydroxybutyrate which leads to brain-derived neurotophic factor (BDNF). BDNF stimulates and controls growth of new neurons from neural stem cells (neurogenesis).

Blood sugar slightly above normal is bad news

Blood sugar above 105 to 110 may be a cognitive hazard.

High-normal glucose shrinks the brain: keep blood sugar low!

Shown by a study of 266 men and women between the ages of 60 and 64: Even in the sub-clinical range and in the absence of diabetes, monitoring and management of plasma glucose levels could have an impact on cerebral health.”

Shown by 249 cognitively healthy non-diabetic individuals aged was 60-64: people whose blood sugar is on the high end of the normal range may be at greater risk of brain shrinkage that occurs with aging and diseases such as dementia.

Shown by a study 249 people in their early 60s whose blood sugar was “high-normal”: significant brain shrinkage among those whose blood sugar levels were high but still below the World Health Organization’s threshold for pre-diabetes.

Shown by a study of 104 healthy adults (ages 18 to 78) without diagnoses of diabetes or hypertension:  high-normal blood glucose levels were associated with decreased delayed associative memory, reduced accuracy of working memory processing among women, and slower working memory processing among men.


Blood glucose levels even at the normal range can have a significant impact on brain atrophy in ageing.


Shown by a study of 240 healthy adults: Senior moments, also dubbed by New York Times Op-Ed columnist David Brooks as being “hippocampally challenged,” are a normal part of aging. Such lapses in memory, according to this new research, could be blamed, at least in part, on rising blood glucose levels as we age. The findings suggest that exercising to improve blood sugar levels could be a way for some people to stave off the normal cognitive decline that comes with age.


Shown by a study of 2067 participants without dementia: higher glucose levels may be a risk factor for dementia, even among persons without diabetes. 


Shown by a study of 124 cognitively normal, non-diabetic adults with a family history of Alzheimer’s disease: high blood sugar is an Alzheimer’s risk.


Shown by a study of 1,173 people, aged 75: moderately high blood sugar is an Alzheimer’s risk.


Shown by a study of 2067 participants without dementia: higher glucose levels may be a risk factor for dementia, even among persons without diabetes.


This systematic review and meta-analysis of 144 prospective studies concluded that prediabetes is a risk factor for all-cause dementia, alzheimer’s disease, and vascular disease.

High after-meal (postprandial) blood glucose is a cognitive hazard. Less simple carbs (complex carbs are better) helps. Here is WebMD on controlling postprandial blood glucose. Tommy Wood MD, PhD, in conversation with Dr Rangan Chatterjee explains the cognitive hazard of blood glucose spikes.

There is a time of day difference in postprandial glucose and insulin responses: late evening meals produce a bigger blood glucose spike that meals eaten earlier in the day.

Higher blood sugar is even more of a cognitive threat

Perturbed cerebral glucose metabolism is a feature of more severe Alzheimer’s.


Hyperglycemia results in reduced hippocampal microstructure. High fasting glucose causes whole brain atrophy. Keep blood sugar low to avoid brain atrophy.


High fasting glucose increases brain glucose and causes hippocampal atrophy.


High blood sugar→vascular dementia and other dementia.


Shown by a study of 5,189 people over 10 years: high HbA1c level is a cognitive threat. Even among individuals with HbA1c <6.5% (threshold for diabetes), higher HbA1c was associated with memory decline.


The A1C chart below can help a person convert and understand their A1C test results. The doctor can provide more context and describe ways to keep blood glucose levels in a safe range.

A1C chart for diabetes

Hyperglycemia increases amyloid-β levels.


Hyperglycemia increases susceptibility to amyloid-β toxicity.


High blood sugar results in abnormally low brain-derived neurotophic factor (BDNF).


High blood sugar injures via inhibition of MIF enzyme activity.


Glycation (caused by high blood sugar) damages an enzyme called MIF (macrophage migration inhibitory factor).


Hyperglycemia impairs neural activity in ways that are similar to what is observed in preclinical Alzheimer’s disease models.


Low blood sugar is also hazardous. SIRT3 may protect the brain during hypglycemia. SIRT3 is increased by exercise.


Too much insulin can lead to neuroinflammation. Insulin is raised the most by eating sugar, and simple carbs.
If one pursues a low-carb diet, do it right: Animal-based low-carb diets were associated with an increased risk of developing Type 2 diabetes, while plant-based low-carb diets were associated with a lower risk of developing diabetes.


Keep blood sugar low to avoid oxidative stress.

Controlling blood sugar

Blood sugar tends to rise with advancing age, even when one remains slim and continues to exercise.


9 weeks of daily intake of 7.4 g of fructooligosaccharides (FOS) was tested on a group of elderly people. The prebiotic consumption did not adversely affect intestinal transit and led to a decrease in serum glucose. Here are food sources of fructooligosaccharides.


Rice, bread  and potatoes raise blood sugar almost a rapidly as sugar does. WebMD: Refined carbohydrates, even ones that don’t taste super sweet, can spike your blood sugar. That’s often followed by a crash, which can make you feel mentally foggy. Research shows that too many refined carbs may increase your risk of Alzheimer’s disease, especially in certain people who are genetically predisposed to it. 


White Bread and White Rice

Due to differences in the gut bacteria, people’s glycemic respond to various foods can be wildly different. So, don’t assume that a good diet will control blood sugar. Check it/get it checked if there is any doubt. This is what high blood sugar feels like.


For those with stubbornly high blood sugar, Metformin might help. Metformin works by inhibiting the functioning of mitochondria, which explains many complaints about how it makes exercise more difficult.


Beetroot juice, despite the high natural sugar content, has not been found to raise blood sugar or insulin response. Beetroot juice powder is available.

Intermittent fasting

Dietary restriction increases insulin sensitivity and lowers blood glucose in rhesus monkeys. For most, though, intermittent fasting may be preferable.


Medical News Today says “Time-restricted feeding seems to be beneficial for most people who are not experiencing acute illness or taking medications to lower blood sugar, for type 2 diabetes, for example.”


One lifestyle modification that may  help control blood sugar is intermittent fasting by eating only early in the day. Eating only early in the day is best for anyone who struggles with blood sugar. If that is too hard, eat starches early, and fats later in the day.


Early time-restricted feeding, a form of intermittent fasting (IF) that involves eating early in the day to be in alignment with circadian rhythms in metabolism improves some aspects of cardiometabolic health and that IF’s effects are not solely due to weight loss.

This systematic review and meta-analysis showed that intermittent fasting diets have certain therapeutic effects on blood glucose and lipids in patients with metabolic syndrome and significantly improve insulin resistance.


Consuming a bigger portion of daily caloric intake during the first half of wakeful hours may be preferred for better blood glucose regulation and weight control.


Time-restricted eating may lower blood sugar more than medication. This paper was discussed by Dr. Roger Seheult: 
As shown in that paper: the control group’s HbA1c diminished 8% but the time-restricted eating group diminished 18% in 12 weeks. A diabetic medication might only reduce HbA1c by 7%. Instantaneous blood sugar also seriously decreased. The diabetic patients also lost significant weight via only intermittent fasting for 12 weeks.

Resistance training (stretch bands, lifting weights) will  help control blood sugar by building muscle.


Combining high intensity interval training with intermittent fasting helped improve metabolism in healthy overweight women.


Dietary restriction increases insulin sensitivity and lowers blood glucose in rhesus monkeys.


Be slim, drink water as a beverage, consume dietary fiber, minimize simple carbs, and exercise regularly.


A 2012 study found that incorporating legumes into the diet improved glycemic control and lowered the risk of coronary heart disease in people with type 2 diabetes.


  • Apple cider vinegar. According to older research, this vinegar may reduce blood sugar levels by delaying the emptying of your stomach after a meal.
  • Cinnamon. This spice may improve blood sugar levels by enhancing insulin sensitivity and slowing the breakdown of carbs in your digestive tract. This moderates the rise in blood sugar after a meal. Nevertheless, more research is needed.
  • Fenugreek seeds. While more high quality studies in humans are needed, there is some weak evidence that fenugreek may help support blood sugar management.


Berberine: Research suggests that this compound lowers blood sugar by stimulating enzymes’ breakdown of glucose, promoting your tissue’s use of sugar and increasing insulin production. Berberine doesn’t work for everyone. Doctors don’t usually  recommend berberine due to it’s poor absorption. Metformin is used instead.

Cocoa – Yum!

This meta-analysis of observational studies found that the consumption of cocoa/dark chocolate reduced the
serum fasting blood glucose (FBS) and LDL cholesterol concentrations of diabetic participants.


This systematic review and meta-analysis based on both long-term and short-term randomised controlled trials showed the beneficial long-term effects of cocoa products intake on cardiometabolic biomarkers for T2D, especially on blood glucose, lipid metabolism (LDL-C and TG), and inflammation (CRP).

This double-blind, placebo-controlled trial of 50 obese type 2 diabetic patients (BMI ≥ 24.0; fasting blood glucose ≥ 7.0 mmol/L or postprandial blood glucose ≥11.1 mmol/L) were randomly assigned to curcuminoids (300 mg/day) or placebo for 3 months. Curcuminoids supplementation significantly decreased fasting blood glucose (p < 0.01), HbA1c (p = 0.031), and insulin resistance index (HOMA-IR) (p < 0.01) in type 2 diabetic patients.


In a study of 1,978 older adults publishing Sept. 21 in the journal Scientific Reports, researchers at Duke Health and the Duke Clinical Research Institute found people with irregular sleep patterns weighed more, had higher blood sugar, higher blood pressure, and a higher projected risk of having a heart attack or stroke within 10 years than those who slept and woke at the same times every day.


Several nights of just 4 h of sleep in otherwise healthy individuals impairs blood sugar regulation to such an extent that you would be classified as pre-diabetic.


Poor sleep efficiency and later bedtime routines are associated with more pronounced postprandial glycaemic responses to breakfast the following morning.

Skipping breakfast can result in a significantly higher glycaemic response after lunch as compared with the glycaemic response after an identical lunch when breakfast was consumed.


Poor Sleep Linked With Higher Blood Sugar | NIH News in Health

Amla (Indian gooseberry) can lower blood sugar. Here is a video about it. Dried whole amla fruits are available at Mountain Rose Herbs.


Lipoic acid (from green leafy veggies) may lower blood sugar.


A mouse study showed that a small dose of BDNF was found to be effective in lowering blood glucose concentration. This indicates that BDNF regulates glucose metabolism by acting directly on the brain.


Australian scientists have shown that brown fat – a special type of fat that burns energy to produce heat – may also help to keep blood sugar steady in adults.


Mayo Clinic: For most young, healthy adults, caffeine doesn’t appear to noticeably affect blood sugar (glucose) levels, and having up to 400 milligrams a day appears to be safe.


Corriander lowered blood sugar in rats.


This double-blind, placebo-controlled trial of 100 diabetic patients found that curminoids lower blood sugar, partially due to decrease in serum free fatty acids.

Curcumin is useful for controlling blood sugar

This review of studies published in PubMed from 1998 to 2013 found that curcumin can reduce blood glucose level by reducing the hepatic glucose production, suppression of hyperglycemia-induced inflammatory state, stimulation of glucose uptake by up-regulation of GLUT4, GLUT2 and GLUT3 genes expressions, activation of AMP kinase, promoting the PPAR ligand-binding activity, stimulation of insulin secretion from pancreatic tissues, improvement in pancreatic cell function, and reduction of insulin resistance.

This systematic review and meta-analysis of 11 randomized controlled trials found that supplementation of isolated curcumin or combined curcuminoids were both effective in lowering the FBG concentrations of individuals with some degree of dysglycemia, but not in non-diabetic individuals. Isolated curcumin lead to significant decreases of the HbA1c compared to placebo.

Exercise to the rescue!

Exercise will increase insulin sensitivity, thus improving blood sugar control. Controlling blood sugar swings is important because hypoglycemic episodes are also a risk for dementia.


Exercise works via transforming growth factor beta 2 (TGF-beta 2).


A systematic review and meta-analysis of available data published in Diabetologia (the journal of the European Association for the Study of Diabetes) suggests that combined aerobic and resistance training, rather than either alone, is best for controlling both blood sugar.


The white muscle that increases with resistance training, age and diabetes helps keep blood sugar in check.


There is a bell-shaped relationship between exercise training load and mitochondrial function, glucose metabolism, and physiological adaptation to exercise training in human subjects, during a training program with a progressive increase in training load. In this study of 11 healthy volunteers, excessive exercise training caused mitochondrial functional impairment and decreased glucose tolerance in healthy volunteers. There was a substantial improvement in metabolic parameters after only 1 week of reduced training in the recovery phase compared with the excessive training phase.


Afternoon exercise will lower blood sugar more than morning exercise. Caffeine in the morning will cause morning exercise to lower blood sugar similar to afternoon exercise. Moderate-to-vigorous physical activity in the afternoon led to an 18% reduction in insulin resistance, and the same types of activity in the evening were linked to a 25% reduction.


This systematic review and meta-analysis concluded that exercise plays an important role in optimizing glycemic control and improving quality of life (QoL), BMI, and waist circumference in type 2 DM patients. Exercise could be a safe adjunct therapy to medical treatments in these patients.

This meta-analysis of 17 randomized controlled trials found that green tea had favorable effects, for decreased fasting glucose and Hb A1c concentrations. is a long-term measure of blood sugar


This systematic review and meta-analysis of 27 randomized controlled trials involving 2194 subjects found that, in short-term trials, green tea supplementation significantly reduced fasting glucose, but had no significant effect on fasting insulin and HbA1c . (HbA1c. is a long-term measure of blood sugar).




By Otto

I am a health enthusiast, engineer, and maker.


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