Category: John J. Oró, MD

Eating Lots of Carbs, Sugar May Raise Risk of Cognitive Impairment, Mayo Clinic Study Finds

Those 70-Plus Who Ate Food High In Fat And Protein Fared Better Cognitively, Research Showed

That’s it. That’s the title of an article recently in posted on the Mayo Clinic website on October 16. It doesn’t get much more Paleo than that.

The study by Mayo Clinic epidemiologist Rosebud Roberts, M.B., Ch.B. and colleagues was published in January 12, 2012 in the Journal of Alzheimer’s Disease. While the type of carbs is not listed in the abstract, carbs in the typical U.S. diet are mostly grains and added sugars.

“Those who reported the highest carbohydrate intake at the beginning of the study were 1.9 times likelier to develop mild cognitive impairment than those with the lowest intake of carbohydrates. Participants with the highest sugar intake were 1.5 times likelier to experience mild cognitive impairment than those with the lowest levels.”

“But those whose diets were highest in fat — compared to the lowest — were 42 percent less likely to face cognitive impairment, and those who had the highest intake of protein had a reduced risk of 21 percent.”

“When total fat and protein intake were taken into account, people with the highest carbohydrate intake were 3.6 times likelier to develop mild cognitive impairment.”

The conclusion from the abstract:

“A dietary pattern with relatively high caloric intake from carbohydrates and low caloric intake from fat and proteins may increase the risk of MCI or dementia in elderly persons.”

Bottom line: More evidence Paleo nutrition sustains brain health. More evidence the low-fat advice is mistaken.


J Alzheimers Dis. 2012 Jan 1;32(2):329-39. doi: 10.3233/JAD-2012-120862.
Relative intake of macronutrients impacts risk of mild cognitive impairment or dementia.


Andrea (name changed) is in her 40’s and runs a busy household. For a few months, she had been waking up with a headache. Not daily at first, though recently they had become more frequent. The headache would resolve after being up a while, but recently it has lingered through the day.

She scheduled a visit with her family doctor.  There, she described a frontal, throbbing, and, at times, sharp headache. The past couple of weeks, she reported, episodes of numbness and weakness in the right hand and dizziness when changing positions.

A neurological examination revealed moderate difficulty walking with one foot in front of the other. Otherwise, the exam was normal. Her provider ordered an MRI of the brain which revealed the ventricles (spinal fluid spaces inside the brain) to be somewhat larger than normal – a condition called hydrocephalus (Figure 1). Something was blocking the flow of spinal fluid through the ventricles, but what could it be?

Figure 1 – Cross-section MRI showing enlargement of the ventricles (dark fluid filled spaces) in the center of the brain.

In the side view (sagittal) MRI, a tumor could be seen inside of the fourth ventricle, the fluid space between the brainstem and the cerebellum (Figure 2).  A cross section MRI scan (Figure 3), performed after she had received received intravenous contrast (“dye” material given through a vein), clearly outlined the tumor (Figure 3). It was blocking blocking cerebrospinal fluid (CSF) flow and enlarging the ventricle. This explained why the ventricles in the upper brain looked too big.

Figure 2 – Side view MRI of the brain showing the tumor between the brainstem and the cerebellum.

Figure 3 – Cross section view of the lower brain area. The tumor is easily after intravenous contrast was given.

There are various treatments for brain tumors. Some tumors are first diagnosed with a needle biopsy, while others may be treated with specialized radiation called radiosurgery. However, in many cases, surgery is required to remove the tumor. In Andrea’s case, the tumor was blocking CSF flow. If the blockage became worse, which was very likely since the tumor would keep growing, it could render her unconscious and jeopardize her life. A needle biopsy would not resolve the CSF blockage. 

After careful discussions with her and her husband, she was readied for surgery. The plan was to reach the tumor through a cranial opening (craniotomy) at the back of the head.  Once the membrane surrounding the brain was exposed and opened, a path would be developed between the two halves of the lower cerebellum (called the cerebellar tonsils).  With gentle separation of the cerebellar tonsils, the lower part of the tumor came into view (Figure 4).

Figure 4 – Microphotograph during surgery showing the lower portion of the tumor between the cerebellar tonsils.

After a biopsy was obtained, the tumor was removed through microsurgery using the neurosurgical microscope, microsurgical instruments, and an ultrasonic aspirator – an instrument whose tip vibrates at ultrasonic frequencies and morselize (break-down) the cells. (This tool has replaced the laser that came into use in the 1980’s, although there are still a few applications for it today). Using the gentle action of the ultrasonic aspirator and microsurgical dissection, the tumor was steadily removed. Inspection of the floor of the fourth ventricle showed no residual tumor (Figure 5).

Figure 5 – View of the bottom of the fourth ventricle after the tumor was removed.

Andrea stayed in the hospital for … days and was then discharged home with her family. She steadily resumed her normal activities. Follow-up brain MRI scans have shown no residual tumor (Figure 6). Happily, she has recovered completely and is back to her busy life.

Figure 6 – MRI scan performed 7 months after surgery shows no evidence of tumor.

Tumors growing within the cerebral ventricles are rare in the adult population. In one study of 73 persons with intraventricular tumors, the types of tumor found included:

  • medulloblastoma
  • ependymoma
  • epidermoid
  • cystercircosis
  • astrocytoma
  • subependymoma

Other tumors found within the ventricles are a choroid plexus papillomas and meningiomas. A metastasis from a tumor elsewhere in the body can also develop within the ventricles.

The pathological examination of Andrea’s tumor revealed it to be a choroid plexus papilloma. Follow-up MRI scans within the first year following surgery have shown no tumor.  The chances of the tumor coming back from unseen cells buried within the tissues are about 10%. MRI scans will be performed on a regular basis for a few years.


Intraventricular mass lesions.

Morrison G, Sobel DF, Kelley WM, Norman D.

Radiology. 1984 Nov;153(2):435-42.

Sleep is fundamental to good health. Sleep impacts the quality of your day, and what happens during the day impacts the quality of your sleep. While many factors affect sleep, one we can control, yet often don’t, is the intensity of light we are exposed to before bedtime.

As we saw in The End of Night, the development of the light bulb and alternating current allowed us to effectively eliminate night at will. Since most of us prefer to get a good night’s sleep, recall during the Paleolithic the slow decrease in light intensity at dusk prepared the brain for sleep, primarily by the secretion of melatonin. Today, we often keep the room lights on until bedtime and then, once turned off, expect to fall asleep effortlessly. For millions of Americans, the failure to adequately prepare the brain results in nonrestorative sleep.

According to EurekAlert, the Journal of Clinical Endocrinology & Metabolism will publish an article comparing normal room light versus dim light on the secretion of melatonin:

In this study, researchers evaluated 116 healthy volunteers aged 18-30 years who were exposed to room light or dim light in the eight hours preceding bedtime for five consecutive days. An intravenous catheter was inserted into the forearms of study participants for continuous collection of blood plasma every 30-60 minutes for melatonin measurements. Results showed exposure to room light before bedtime shortened melatonin duration by about 90 minutes when compared to dim light exposure. Furthermore, exposure to room light during the usual hours of sleep suppressed melatonin by greater than 50 percent.

Lead author Joshua Gooley, PhD concludes:

Our study shows that this exposure to indoor light has a strong suppressive effect on the hormone melatonin. This could, in turn, have effects on sleep quality and the body’s ability to regulate body temperature, blood pressure and glucose levels.

While it is not practical to dim the lights for 8 hours prior to sleep, at least an hour of dim light should help those with difficulty initiating sleep. A good solution is to install dimmer switches in the rooms most frequented at dusk and a dimmer switch on the nightstand lamp. As we create our own modern Paleolithic, maybe homes in the future will be programmable to dim electric lighting automatically at a set time and rate.


Alzheimers and Diet

There are currently 5.4 million people with Alzheimer’s disease in the United States, and “barring medical breakthroughs,” by 2050 that number is projected to grow to as much as sixteen million. According to the Alzheimer’s Association’s 2011 Facts and Figures, “between 2000 and 2025, some states and regions across the country are expected to experience double-digit percentage increases in the overall number of people with Alzheimer’s.” Nor is the United States alone in experiencing an increase in this disease. A recent study reported a growth in the number of cases in Beijing, and in Britain the Prince of Wales last year warned of a coming epidemic. 

This surge is attributed to the growing elderly populations in both developed and developing countries. As deaths from other causes like heart disease decrease, the number of deaths attributable to Alzheimer’s, and especially Alzheimer’s-related pneumonia, are increasing. And even when it doesn’t kill those it afflicts, Alzheimer’s often significantly reduces life expectancy, with “61 percent of people with Alzheimer’s at age 70 […] expected to die before age 80 compared with 30 percent of people at age 70 without Alzheimer’s.”

Alzheimer’s disease is a common form of dementia, accounting for between sixty to eighty percent of all cases. It develops slowly, appearing as memory and mood problems, like forgetfulness, apathy, and depression. Over months and years, the disease progresses, causing “impaired judgment, disorientation, confusion, behavior changes, and difficulty speaking, swallowing, and walking.” The person affected by Alzheimer’s is gradually rendered helpless by this disease. Those who can afford to become reliant upon the care of trained professionals, while those who cannot must rely on the assistance of family members and other unpaid caregivers.

Though the greatest factor in the development of Alzheimer’s is advancing age, it is a disease, and “not a normal part of aging.” The risk of developing Alzheimer’s is generally agreed to be augmented by multiple factors, among them poor cardiovascular health, the presence of diabetes and hypertension, physical inactivity, and smoking and obesity.

Unfortunately, the precise cause of Alzheimer’s remains unknown. While researchers understand more and more about the mechanism by which this disease operates, no effective treatment exists to cure it.

The hallmarks of the disease, revealed in post-mortem autopsies, are the plaques and tangles that damage the brains of Alzheimer’s sufferers. Plaques are deposits of the protein beta-amyloid that gather upon brain cells, while tangles are accumulations of the protein tau, which collect within the cells themselves. New science suggests that beta-amyloid is produced in the liver of Alzheimer’s sufferers, and that it gathers upon brain cells after having been brought there by the cardiovascular system. One study found that beta-amyloid strips insulin receptors from neurons, thus increasing resistance to insulin, which is necessary for the formation of memories. This finding has led to speculation that Alzheimer’s could be a third type of diabetes. Another study, reported in the New York Times, found that the progression of Alzheimer’s was slowed by nasally administering doses of insulin to those suffering from it.

But perhaps most interesting is the research suggesting that diet can play a powerful role in the prevention of this disease. In the study “Nutrition and Alzheimer’s Disease: The Detrimental Role of a High-Carbohydrate Diet,” the authors begin by stating that “an excess of dietary carbohydrates, particularly fructose, alongside a relative deficiency in dietary fats and cholesterol, may lead to the development of Alzheimer’s disease.” They then assert that eating too many carbohydrates “leads to a cholesterol deficiency in neurons, which significantly impairs their ability to function.”

From a Paleo perspective, the modern American diet can aggravate many of our contemporary ailments, including Alzheimer’s. While evidence to support this suspicion is still not definitive, there is ethnographic research noting the absence of senile dementia in traditional societies that avoid industrial foods. The Kitava Study observed the health of the inhabitants of the remote Melanesian island of Kitava, “one of the last populations on Earth with dietary habits matching what would have been the case for the population of Homo sapiens in their original habitats.” The Kitavans eat a unique Paleo diet that is 95% vegan, consisting mostly of vegetables and tubers, and which is supplemented by fish. Senile dementia is completely unknown in Kitavan society; not only was none discovered by researchers, but no Kitavan surveyed could recall having witnessed a case. This absence of Alzheimer’s in traditional societies is echoed by Dr. Hugh Trowell, a British physician who managed a psychiatric ward in Nairobi during the colonial period, and who reported that among the disorders affecting his patients “senile dementia was a notable absentee.

While dietary modification is probably a good way to reduce the risk of developing Alzheimer’s, until stronger evidence appears in its favor, it should be regarded as a preventative measure, and not a guaranteed method of avoiding this disease.

(Unless otherwise noted, all information cited in this blog came from the Alzheimer’s Association’s 2011 Facts and Figures.)

The first signs of human consciousness were found in Blombos Cave, South Africa and date to 70 to 80 thousand years ago. It is probably no accident that the site is littered with evidence of seafood consumption. Indeed, significant inclusion of seafood and fish in the human diet may represent the final nutritional factor in development of the human mind. 

 The typical American diet is profoundly different from that of our Paleolithic ancestors and is increasingly considered the root of many modern diseases.

In a new study reported by EurekAlert, researchers at Rhode Island Hospital’s Alzheimer’s Disease and Memory Disorders Center revealed older adults taking fish oil supplements preserved brain volume and had smaller cerebral ventricles (a healthy sign suggesting less brain atrophy). Lead investigator, Lori Daiello, PharmD, states:

 “In the imaging analyses for the entire study population, we found a significant positive association between fish oil supplement use and average brain volumes in two critical areas utilized in memory and thinking (cerebral cortex and hippocampus), as well as smaller brain ventricular volumes compared to non-users at any given time in the study. In other words, fish oil use was associated with less brain shrinkage in patients taking these supplements during the ADNI study compared to those who didn’t report using them.”

 This observational study is just one additional piece of evidence demonstrating our continued movement away from the original human diet comes at a price. In this case, a shrinking brain.