From The Desk Of Clarence Bass
“When it comes to benefiting cognitive function, the diet that may be the most
beneficial is the Mediterranean diet, which is rich in seafood, omega-3 fatty
acids, and plant-based foods.”
Carbs and the Brain
Grain Brain in the Spotlight
In late summer 2013, two related events occurred within weeks of each other. One was duly noted in medical and health publications—the other was everywhere: The Dr. Oz Show to The Atlantic to The New York Times. On August 8, a study appeared in the New England Journal of Medicine establishing, for the first time, a link between dementia and elevated blood sugar—in non-diabetics. While September 17 saw the release of Grain Brain: The Surprising Truth About Wheat, Carbs, and Sugar—Your Brain’s Silent Killers. Neurologist David Perlmutter, the author, declared yet another war on carbohydrates in our diet. Grains, including whole grains, were squarely in his sights. You can guess which got the most press.
I believe the emphasis was misplaced. One carried a health message we can all use and the other, with the best of intentions, gave health seekers an axe when they needed a paring knife.
Don’t let me dissuade you from reading Grain Brain. Read it, but be warned that it will scare the hell out of you. Dr. Perlmutter is apparently liked and respected by his colleagues. Much of what he writes is no doubt correct. That, however, will not be my focus. To the contrary, with the help of authoritative sources, I’m going to make the case that the good doctor’s zeal got ahead of his evidence. I’ll also tell you what you can do to protect your brain—I promise not to upset you—along with some minor adjustments I’ve made in my own diet.
Let’s start with some basic facts that cast doubt on Dr. Perlmutter’s claim that carbs, even healthy carbs such as whole grains and fruit, are silently killing our brain.
Perlmutter tells readers “that an extremely low-carbohydrate but high-fat diet is ideal (we’re talking no more than 60 grams of carbs a day—the amount in a serving of fruit).” He advocates eating closer to the "ancient ancestral diet" that he characterizes as 75% fat, 20% protein, and 5% carbs. “Fat—not carbohydrate—is the preferred fuel for human metabolism and has been for all of human evolution,” Perlmutter maintains.
The 5th Edition of the textbook Biochemistry says otherwise for the brain: “Glucose [blood sugar] is virtually the sole fuel for the human brain, except during prolonged starvation. The brain lacks fuel stores and hence requires a continuous supply of glucose…Fatty acids do not serve as fuel for the brain, because they are bound to albumin in plasma and so do not traverse the blood-brain barrier. In starvation, ketone bodies generated by the liver partly replace glucose as fuel for the brain.”
I learned this the hard way when cutting carbs in preparation for the Mr. America Past 40 contest. In my book Ripped, I told how two nectarines brought me out of a stupor caused by depriving my body of carbohydrates: Within minutes, the carbohydrates from the nectarines had their effect. I felt like a new person. My body was no longer being forced to work overtime converting fat and protein to provide for my energy needs. The carbohydrates in the nectarines were quickly and easily converted to the glucose (blood sugar) that my brain required to function properly. I left the house an exhausted Mr. Hyde and returned a revived Dr. Jekyll.
David Katz, MD, called Dr. Perlmutter’s assertion that the Stone Age diet was 75 percent fat “wildly preposterous.” (James Hamblin, The Atlantic, December 2013). Katz, founding director of Yale University’s Prevention Research Center and author of a widely used nutrition textbook for health care professionals, explained that Paleolithic humans ate mostly plants with a scattering of seeds and nuts. “They only started adding oil to the diet after the Dawn of Agriculture,” he continued. “What the hell could they possibly have eaten that would be that fatty?”
"There is no evidence I'm aware of that early humans routinely ate a 75% fat diet," Susan Roberts, PhD, director of the Tufts University HNRCA Energy Metabolism Laboratory, who has studied such ideas, told the Tufts Health & Nutrition Letter. (March 2014)
Lastly, in an interview appearing January 21, 2014, in Medscape, Dr. Perlmutter was asked to explain his claim that whole grains—typically assumed healthy—increase dementia risk.
“Yes, they do,” he responded, referencing the glycemic index, which measures the elevation of blood sugar after eating specific foods. “When you look at the glycemic index of whole-grain bread, for example, it’s extremely high: 72-74. It’s higher than that of white bread. It’s much higher than that of many candy bars.”
He must be using a different glycemic index than Dr. Barbara Rolls, professor of nutritional sciences at Penn State University and the creator of the widely acclaimed Volumetrics theory of weight control, who wrote in her latest book, The Ultimate Volumetrics Diet: “Proponents say that by choosing foods with a low GI instead of those with a higher GI—for example, whole grains rather than processed grains—you can prevent big rises and drops in glucose and insulin.”
Drew Ramsey, MD, an assistant clinical professor of psychiatry at Columbia University College of Physicians and Surgeons, called Perlmutter’s glycemic index argument “misleading.” (Medscape 1-30-14) “The argument is that a piece of wheat bread has a higher glycemic index than sugar, but this is really very slight of hand because half of sugar is [manufactured] fructose, and fructose doesn’t register on the glycemic index because it doesn’t raise blood sugar insulin—it raises fructose levels,” Ramsey explained.
Another distortion is the different amounts of carbohydrates in the foods being compared. To equal the amount of available carbohydrate in 50 grams of sugar (the amount used in the glycemic index), you'd need more than four slices of whole wheat bread. (Tufts Health & Nutrition Letter, March 2014)
Here are the facts on the GI of bread: “The type of bread you eat and the level of refinement of the ingredients has an impact on the GI of the bread. Pumpernickel, which is a dark, dense bread, has a low GI of 50. White bread, which is more processed, has a high GI of 73—that’s higher than table sugar, which has a GI of 68. You should try to limit your consumption of white bread.” (Dr. Peter Nickles, October 27, 2013, Livestrong.com) For whatever reason, Dr. Perlmutter’s GI figures pertain not to whole grain bread, but to white bread.
Now, let’s move on to the big picture.
Perhaps the most powerful statement by Dr. Perlmutter’s detractors is that there just isn’t enough evidence to support a wholesale clamp down on one of the three cornerstones of our diet. One of the most articulate spokesman for this position is Dr. Chris Kresser, an integrative medicine practitioner known for his reliance on lifestyle, diet, and prevention. “Modern research does not support the notion that ‘safe’ carbs are harmful,” Kresser wrote in response to patient queries about Grain Brain. (chriskresser.com)
“When an author or expert recommends excluding or severely limiting one of three macronutrients that humans consume, the evidence demonstrating harm should be strong—not only because of the inconvenience of following such a restricted diet, but because extreme diets (ketogenic or very low carbohydrate diets in this case) are not always harmless,’ Kresser explained. “In my practice I’ve seen many patients who’ve worsened on long-term VLC diets….”
As noted at the top of this piece, we have new evidence of a connection between above-normal blood sugar and dementia--the loss of memory and thinking skills that afflict millions worldwide. Let’s talk about that next.
Blood Sugar and Dementia
Diabetes is a well-established risk factor for dementia. The new study, led by Dr. Paul K. Crane, Harborview Medical Center, Seattle, WA, for the first time, found a link between dementia and blood sugar in the pre-diabetes range. Normal blood sugar is under 100 after an eight-hour fast. You have diabetes if your reading is 126 or higher. People with blood sugar in between, above 100 but below 126, are called prediabetic. Nearly 80 million Americans are in this category.
Dr. Crane and his colleagues followed 2067 men and women, average age 76, for an average of 6.8 years; 232 participants had diabetes and 1835 did not. The researchers found that any increase in blood sugar was associated with an increased risk for dementia—the higher the blood sugar, the greater the risk.
Dementia developed in 524 participants, 74 (32%) with diabetes and 450 (24.5%) without diabetes. Participants with a glucose level of 115 had an 18 percent great risk of developing dementia than those with a reading of 100. Among those with diabetes, participants with a glucose level of 190 had a 40 percent greater risk of dementia than those with a fasting blood sugar of 160.
It’s important to remember that an association between moderately elevated blood sugar and risk of dementia doesn’t necessarily prove causation. It does, however, show a connection—David Nathan, MD, a Harvard Medical School professor who took part in the study, called it “convincing.” It’s the best evidence we have at the present time. We know that elevated blood sugar can lead to a variety of health problems including heart, eye, kidney, and nerve disease. Pre-diabetics can now add dementia to that list.
“Our findings…suggest the need for intervention that reduce glucose levels,” the researchers wrote in their report.
What can we do to control blood sugar and protect our brain? More than enough—without avoiding whole grains or subjecting ourselves to a very low carb diet. Let’s talk about diet—and then exercise.
Eating for a Healthy Brain
What matters most is diet as a whole. Each component of diet interacts with other components in highly complex ways. Extreme reduction of a macronutrient is likely to cause more harm than good.
I’ve already told about my experience with the low carb diet. I also learned the hard way that cutting fat across the board can trigger a rise in triglycerides—adding good fat in the form of flaxseed oil dropped my triglycerides 50 percent. Low protein diets impair the body’s ability to build, repair, and maintain itself. When aiming to improve health outcomes, it’s best to focus on improving your diet across the board.
Felice N. Jacka, PhD, Deakin University, Melbourne, Australia, has conducted a series of studies showing a poor diet to be associated with cognitive deficits. “There is no one food that should be eaten or not eaten to reduce the risk for mental disorders or any other health disorder,” she told Medscape Medical News (1-30-14). When pressed, she listed refined carbohydrates—foods with refined grains and added sugars—and trans fats as the most detrimental. Diets which spike blood sugar, increasing inflammation and oxidative stress, are linked to psychiatric disorders, she added.
Dr. Ramsey agreed: “I encourage my patients to think of dietary patterns—it’s not that you can’t eat a piece of cake, it’s just that that cake comes with no nutrients that your brain needs to deal with all of the calories.” Like most highly refined foods, cake contains loads of sugar and practically no fiber to slow its digestion; the sugar main-lines into your bloodstream. Fiber slows digestion and is one of the primary reasons to include whole grains in your diet.
“If you think about a patient eating the modern American diet—empty carbs [and all the rest]—and you help them shift to a whole-food, nutrient-dense diet, consisting of leafy greens, seafood, whole grains, and nuts, there [is likely to be an] improvement in mood,” Ramsey added. “I have definitely seen that.”
The diet which appears to have the best of everything is the Mediterranean diet. “The large PREDIMED randomized trial showed that Mediterranean diets reduce the risk for heart disease, improve cognition, and may also prevent depression. As such, diets high in fruits, vegetables, fish, plant oils, nuts and whole grains, with lower intakes of sugar, processed meat, and animal fats, are likely to be the best bet in supporting the health of our brain as well as the rest of our body.” (Foods That May Harm the Brain, Bret S. Stetka, MD, and Felice N. Jacka, PhD, February 13, 2014; Medscape)
Exercise Wards Off Diabetes and Dementia
Exercise may be the single most important thing you can do to protect against diabetes and mental decline.
The new focus in the control of diabetes is—on muscle. Muscles both consume and store blood sugar. Skeletal muscles, the muscles that move the body, are the body’s biggest consumer of blood sugar. “When you aren’t active, your muscles don’t use or store glucose in a normal, efficient way,” Dr. Tedd Mitchell and his co-authors wrote in Move Yourself: The Cooper Clinic Medical Director’s Guide to All the Healing Benefits of Exercise (Even a Little!) (Wiley 2008). “When the muscle cells don’t open up for sugar intake, as happens in the prediabetic state of insulin resistance, the sugar builds up in the blood.” In short, muscles burn blood sugar during exercise—and exercise makes muscles more receptive (less resistant) to the storage of sugar for future use—when you exercise again.
“The impact of physical activity on blood sugar is spectacular,” the doctors related enthusiastically. Blood sugar drops almost immediately. “If you are physically active today, your body will process glucose better the rest of the day, and tomorrow, and even the day after,” the doctors report. “You can practically argue that nothing in the body responds so positively and so quickly to physical activity as blood sugar.”
A new study from Wales, reported December 9, 2013, in PLoS One, found that exercise is the single most effective lifestyle choice people can make to ward off cognitive decline and dementia.
The 35 year investigation by Cardiff University researchers followed health behaviors of 2,235 men aged 45-59 and recorded the incidence of chronic diseases and dementia. The long-term focus on cognitive decline, dementia, was new.
Following four out of five key behaviors was found to reduce the risk of dementia and cognitive decline by 60 percent, while cutting the risk of heart disease and stroke by 70 percent.
Exercise proved to be more effective than not smoking, controlling bodyweight, healthy eating, and low alcohol consumption.
The recommendation in the Wales study was simply physical activity (any kind) for half an hour five times a week. For the willing, we have evidence that a combination of aerobic exercise and strength training is the most effective preventive for both diabetes and dementia: http://www.cbass.com/DiabetesStrengthVAerobics.htm
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What’s good for your heart is also good for the rest of your body, including your brain. Sensible eating and regular exercise is the way to keep the doctor away and live a long and healthy life.
That’s the formula I live by—and it’s working. My latest visit to the Cooper Clinic in Dallas showed my fasting blood sugar to be 78, well under the 100 upper limit of normal. A fly in the ointment was that my A1c is a hair over the desirable limit, at 5.90. A1c is a measure of average blood sugar over a period of 8 to 12 weeks. The reference range is 4.00 to 5.70.
Doctors have been telling me for years that I probably have a genetic tendency to develop Type 2 diabetes. My father suffered with Type 2 diabetes during the last years of his life. My mother, on the other hand, seemed to be able to eat just about anything without driving up her blood sugar. I think my dad was a bit jealous.
Lynn McFarlin, my present doctor at the Cooper Clinic, says my A1c suggests a mild glucose intolerance. With my whole food diet, very healthy lean body composition, and normal fasting blood sugar, Dr. McFarlin says medical therapy is not warranted. He did, however, encourage me to review my diet and decrease my carbohydrate portions “with a goal of minimizing risk for future diabetes.”
My diet is already quite good—primarily plant-based foods with skim milk, fish, and nuts—but I have found a few ways to make it even better.
As noted here before, I now have a hard-boiled egg and sardines before my "Old Reliable" breakfast mixture--to slow absorption and keep my blood sugar on an even keel.
I was adding a small amount of sugar to my daily cups of tea and coffee (one tea in the morning and one coffee in the afternoon). I now have both without sweetener—and I don’t miss it.
I was also having low-sugar jam with my nut butter bedtime snack. With Carol’s help I have switched to sweet potato or butternut squash with nuts, or quinoa with skimmed milk, blueberries, and sunflower seeds.
Steamed with the skin, sweet potato has a low glycemic index of 46; overcooked without the skin, GI soars to 94. Eating the skin and adding nuts—walnuts, almonds, and pecans—levels blood sugar response even more.
Cooked and eaten the same way, butternut squash has a low GI of 51. Again, nuts slow digestion.
Carol suggested quinoa, which has an estimated glycemic index of 18. It’s good with blueberries, sunflower seeds and skim milk, very satisfying (Whole milk has a GI of 41, and skimmed milk carries a GI value of 32.).
In case you’re wondering, I’m still having a couple of slices of flourless sprouted 100% whole grain bread. The one we use—Ezekiel 4:9 made by Food For Life—has a GI of 43. I have it with hard-boiled egg or nut butter, which slow absorption.
I’ll be going back to the Cooper Clinic in a few months. I’m betting that my A1c will be back in the reference range.
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See also our FAQ Low Carb or Low Fat?
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