David Spero at Diabetes Self-Management has an interesting article about how metformin may prevent cancer and heart disease, and slow the aging process. Metformin is the usual first drug of choice for type 2 diabetes.
Steve Parker, M.D.
David Spero at Diabetes Self-Management has an interesting article about how metformin may prevent cancer and heart disease, and slow the aging process. Metformin is the usual first drug of choice for type 2 diabetes.
Steve Parker, M.D.
One of the major changes in the Western diet over the last century has been the increase in our consumption of omega-6 fatty acids, primarily in the form of industrial seed oils. Examples include oils derived from soybeens, corn, and rapeseed (canola oil). Omega-6 fatty acid consumption in the U.S. increased by 213% since 2009. This may have important implications for development of certain chronic diseases like cancer and heart disease. Excessive omega-6 consumption may be harmful. On the other hand, omega-3 fatty acid consumption may prevent or mitigate the damages. Hence, the omega-6/omega-3 ratio becomes important.
I haven’t studied this issue in great detail but hope to do so at some point. Evelyn Tribole has strong opinions on it; I may get one of her books.
I saw an online video of William E.M.Lands, Ph.D., discussing the omega-6/omega-3 ratio. He mentioned free software available from the National Insitutes of Health that would help you monitor and adjust your ratio.
You can see the video here. Dr. Lands’ talk starts around minute 12 and lasts about 45 minutes. He says it’s just as important (if not more so) to reduce your omega-6 consumption as to increase your omega-3. And don’t overeat.
I’ve found that nearly everbody’s eyes glaze over if I try to explain how, physiologically, the Mediterranean diet promotes health and longevity. Below are some of the boring details, for posterity’s sake, mostly from my 2007 book, The Advanced Mediterranean Diet: Lose Weight, Feel Better, Live Longer.
Many of the nutrient-disease associations I mention below are just that: associations, linkages, not hard proof of a benefit. Available studies are often contradictory. For instance, there may be 10 observational studies linking whole grain consumption with reduced deaths from heart disease, while three other studies find no association, or even suggest higher death rates. (I’m making these numbers up.) If you want hard proof, you’ll have to wait. A long time. Such is nutrition science. Take it all with a grain of salt.
Also note that the studies supporting my claims below are nearly all done in non-diabetic populations.
Coronary Heart Disease
Coronary heart disease, also known as coronary artery disease, is the No.1 cause of death in the world. It’s responsible for 40% of deaths in the United States and other industrialized Western countries. The Mediterranean diet is particularly suited to mitigating the ravages of coronary heart disease. Mediterranean diet cardiac benefits may be related to its high content of monounsaturated fat (in olive oil), folate, and antioxidants.
The predominant source of fat in the traditional Mediterranean diet is olive oil, which is rich in monounsaturated fatty acids. High intake of olive oil reduces blood levels of triglycerides, total cholesterol, and LDL (“bad”) cholesterol. HDL or “good” cho-lesterol is unaffected. Olive oil tends to lower blood pressure in hypertensive people. Monounsaturated fatty acids reduce cardiovascular risk substantially, particularly when they replace simple sugars and easily digestible starches. Monounsaturated fatty acids and olive oil may also reduce breast cancer risk. The cardioprotective (good for the heart) and cancer-reducing effects of olive oil may be partially explained by the oil’s polyphenolic compounds.
Nuts are another good source of monounsaturated fatty acids and polyunsaturated fatty acids, including some omega-3 polyunsaturated fatty acids. Nuts have been proven to be cardioprotective. They lower LDL and total cholesterol levels, while providing substantial fiber and numerous micronutrients, such as vitamin E, potassium, magnesium, and folic acid. Compared with those who never or rarely eat nuts, people who eat nuts five or more times per week have 30 to 50% less risk of a fatal heart attack. Lesser amounts of nuts are also cardioprotective, perhaps by reducing lethal heart rhythm dis-turbances.
Another key component of the Mediterranean diet is fish. Fish are excellent sources of protein and are low in cholesterol. Fatty, cold-water fish are particularly good for us because of their omega-3 polyunsaturated fatty acids: eicosapentaenoic acid (EPA) and docosahexanaenoic acid (DHA). The other important omega-3 polyunsaturated fatty acid is alpha-linolenic acid (ALA), available in certain plants. Our bodies can convert ALA into EPA and DHA, but not very efficiently. Fish oil supplements, which are rich in EPA, lead to lower total cholesterol and triglyce-ride levels. Fish oil supplements have several properties that fight atherosclerosis (hardening of the arteries). In people who have already had a heart attack, the omega-3 polyunsaturated fatty acids have proven to dramatically reduce cardiac deaths, especially sudden death, and nonfatal heart attacks. So omega-3 polyunsaturated fatty acids are “cardioprotective.”
The first sign of underlying coronary heart disease in many people is simply sudden death from a heart attack (myocardial infarction) or heart rhythm disturbance. These unfortunate souls had hearts that were ticking time bombs. I have little doubt that a significant number of such deaths can be prevented by adequate intake of cold-water fatty fish. As a substitute for fish, fish oil supplements might be just at beneficial. The American Heart Association also recommends fish twice weekly for the general population, or fish oil supplements if whole fish isn’t feasible. Compared with fish oil capsules, whole fish are loaded with vitamins, minerals, and protein. The richest fish sources of omega-3 polyunsaturated fatty acids are albacore (white) tuna, salmon, sar-dines, trout, sea bass, sword-fish, herring, mackerel, anchovy, halibut, and pompano.
Cardioprotective omega-3 polyunsaturated fatty acids (mainly ALA) are also provided by plants, such as nuts and seeds, legumes, and vegetables. Rich sources of ALA include walnuts, butternuts, soy-beans, flaxseed, almonds, leeks, purslane, pinto beans, and wheat germ. Purslane is also one of the few plant sources of EPA. Several oils are also very high in ALA: flaxseed, canola, and soybean. Look for them in salad dressings, or try cooking with them.
Omega-3 fatty acid and fish consumption may also be “eye-protective.” Eating fish one to three times per week apparently helps prevent age-related macular degeneration (AMD), the leading cause of blindness in people over 50 in the United States. While AMD has a significant hereditary component, onset and progression of AMD are affected by diet and lifestyle choices. For instance, smoking cigarettes definitely increases your risk of developing AMD. Other foods associated with lower risk of AMD are dark green leafy vegetables, orange and yellow vegetables and fruits: spinach, kale, collard greens, yellow corn, broccoli, sweet potatoes, squash, orange bell peppers, oranges, mangoes, apricots, peaches, honeydew melon, and papaya. Two unifying phytochemicals in this food list are lutein and zeaxanthin, which are also found in red grapes, kiwi fruit, lima beans, green beans, and green bell peppers. Increasing your intake of these foods as part of the Advanced Mediterranean Diet may well help preserve your vision as you age.
Another exciting potential benefit of fish consumption is prevention or delay of Alzheimer’s dementia. Several recent epidemiologic studies have suggested that intake of fish once or twice per week significantly reduces the risk of Alzheimer’s. Types of fish eaten were not specified. No one knows if fish oil capsules are equivalent. For now, I’m sticking with fatty cold-water fish, which I call my “brain food.”
Vitamin E supplements may slow the progression of established Alzheimer’s disease; clinical studies show either modest slowing of progression or no benefit. As a way to prevent Alzheimer’s, however, vitamin E supplements have been disappointing. On the other hand, high dietary vitamin E is associated with reduced risk of developing Alzheimer’s. Good sources of vitamin E include vegetable oils (especially sunflower and soybean), sunflower seeds, nuts, shrimp, fruits, and certain vegetables: sweet potatoes, asparagus, beans, broccoli, Brussels sprouts, carrots, okra, green peas, sweet peppers, spinach, and tomatoes. All of these are on your new diet.
For centuries, the healthier populations in the Mediterranean region have enjoyed wine in light to moderate amounts, usually with meals. Epidemiologic studies there and in other parts of the world have associated reasonable alcohol consumption with prolonged lifespan, reduced coronary artery disease, diminished Alzheimer’s and other dementias, and possibly fewer strokes. Alcohol tends to increase HDL cholesterol, have an antiplatelet effect, and may reduce C-reactive protein, a marker of arterial inflammation. These effects would tend to reduce cardiovascular disease. Wine taken with meals provides antioxidant phytochemicals (polyphenols, procyanidins) which may protect against atherosclerosis and some cancers.
What’s a “reasonable” amount of alcohol? An old medical school joke is that a “heavy drinker” is anyone who drinks more than the doctor does. Light to moderate alcohol consumption is generally consi-dered to be one or fewer drinks per day for a woman, two or fewer drinks per day for a man. One drink is 5 ounces of wine, 12 ounces of beer, or 1.5 ounces of 80 proof distilled spirits (e.g., vodka, whiskey, gin). The optimal health-promoting type of alcohol is unclear. I tend to favor wine, a time-honored component of the Mediterranean diet. Red wine in particular is a rich source of resveratrol, which is thought to be a major contributor to the cardioprotective benefits associated with light to moderate alcohol consumption. Grape juice may be just as good—it’s too soon to tell.
I have no intention of overselling the benefits of alcohol. If you are considering habitual alcohol as a food, be aware that the health benefits are still somewhat debatable. Consumption of three or more alcoholic drinks per day is clearly associated with a higher risk of breast cancer in women. Even one or two drinks daily may slightly increase the risk. Folic acid supplementation might mitigate the risk. If you are a woman and breast cancer runs in your family, strongly consider abstinence. Be cautious if there are alcoholics in your family; you may have inherited the predisposition. If you take any medications or have chronic medical conditions, check with your personal physician first. For those drinking above light to mod-erate levels, alcohol is clearly perilous. Higher dosages can cause hypertension, liver disease, heart failure, certain cancers, and other medical problems. And psychosocial problems. And legal problems. And death. Heavy drinkers have higher rates of violent and accidental death. Alcoholism is often fatal. You should not drink alcohol if you:
■ have a history of alcohol abuse
■ have liver or pancreas disease
■ are pregnant or trying to become
■ may have the need to operate
dangerous equipment or machinery,
such as an automobile, while under
the influence of alcohol
■ have a demonstrated inability to
limit yourself to acceptable
■ have personal prohibitions due
to religious, ethical, or other
Do you ever worry about cancer? You should. It’s the second leading cause of death. Over 500,000 people die from cancer each year in the United States. One third of people in the United States will develop cancer. Twenty percent of us will die from cancer. About half the deaths are from cancer of the lung, breast, and colon/rectum. Are you worried yet?
According to the American Cancer Society, one third of all cancer deaths can be attributed to diet and inadequate physical activity. So we have some control over our risk of developing cancer. High consumption of fruits and vegetables seems to protect against cancer of the lung, stomach, colon, rectum, oral cavity, and esophagus, although other studies dispute the protective linkage. Data on other cancers is limited or inconsistent. If you typically eat little or no fruits and vegetables, you can start today to cut your cancer risk by up to one half. Five servings of fresh fruits and vegetables a day seems to be the protective dose against cancer. Make it a life-long habit. The benefits accrue over time. Fruits and vegetables contain numerous phytochemicals thought to improve or maintain health, such as carotenoids (e.g., lycopene), lignans, phytosterols, sulfides, isothyocyanates, phenolic compounds (includ-ing flavonoids, resveratrol, phytoestrogens, anthocyanins, and tannins), protease inhibitors, capsaicin, vitamins, and minerals.
In addition to cancer prevention properties, fruits and vegetables provide fiber, which is the part of plants resistant to digestion by our enzymes. The other source of fiber is grain products, especially whole grains. Liberal intake of fiber helps prevent constipation, diverticular disease, hemorrhoids, irritable bowel syndrome, and perhaps colon polyps. Soluble fiber helps control blood sugar levels in diabetics. It also reduces LDL cholesterol levels, thereby reducing risks of coronary heart disease. Whether or not related to fiber, high fruit and vegetable intake may reduce the risks of coronary heart disease and stroke. Legume consumption in particular has been associated with a 10 to 20% lower risk of coronary heart disease, with the effective dose being around four servings per week.
Processed, refined grain products have much less fiber than do whole grains. For instance, white all-purpose enriched flour has only about one fourth the fiber of whole wheat flour. The milling process removes the bran, germ, and husk (chaff), leaving only the endosperm as the refined product, flour. Endosperm is mostly starch and 10–15% protein. Many nutrients are lost during processing. The germ is particularly rich in vitamins (especially B vitamins), polyunsaturated fatty acids, antioxidants, trace minerals, and phytochemicals. Phytochemicals protect us against certain chronic diseases. Bran is high in fiber and nutrients: B vitamins, iron, magnesium, copper, and zinc, to name a few. Enriched grain products are refined grains that have had some, but certainly not all, nutrients added back, typically iron, thiamin, niacin, riboflavin, and folate. Why not just eat the whole grain? Whole grain products retain nearly all the nutrients found in the original grain. Hence, they are more nutritious than refined and enriched grain products.
Liberal intake of high-fiber whole grain foods, as contrasted with refined grains, is linked to lower risk of death and lower incidence of coronary heart disease and type 2 diabetes mellitus. For existing diabetics, whole grain consumption can help im-prove blood sugar levels. Three servings of whole grains per day cut the risk of coronary heart disease by about 25 percent compared with those who rarely eat whole grains. Regular consumption of whole grains may also substantially reduce the risk of sev-eral forms of cancer.
Average adult fiber intake in the United States is 12 to 15 grams daily. Expert nutrition panels and the American Heart Association recommend 25 to 30 grams daily from whole grains, fruits, and vegetables.
The health benefits of the Mediterranean diet likely spring from synergy among multiple Mediteranean diet components, rather than from a single food group or one or a few food items.
I recently read Zest For Life: The Mediterranean Anti-Cancer Diet, by Conner Middelmann-Whitney. I give it five stars per Amazon.com’s rating system.
The lifetime risk of developing invasive cancer in the U.S. is four in ten: a little higher for men, a little lower for women. Those are scary odds. Cancer is second only to heart disease as a cause of death in western societies. The Mediterranean diet has a well established track record of protecting against cancers of the prostate, colon/rectum, uterus, and prostate. Preliminary data suggest protection against melanoma and stomach cancer, too. I’m not aware of any other way of eating that can make similar claims.
So it makes great sense to spread the word on how to eat Mediterranean-style, to lower your risk of developing cancer. Such is the goal of Ms. Conner Middelmann-Whitney. The Mediterranean diet is mostly, although by no means excusively, plant-based. It encourages consumption of natural, minimally processed, locally grown foods. Generally, it’s rich in vegetables, fruits, legumes, oive oil, whole grains, red wine, and nuts. It’s low to moderate in meat, chicken, fish, eggs, and dairy products (mostly cheese and yogurt).
Note that one of the four longevity hot spots featured in Dan Buettner’s Blue Zones was Mediterranean: Sardinia. All four Blue Zones were characterized by plant-based diets of minimally processed, locally grown foods. (I argue that Okinawa and the Nicoya Peninsula dwellers ate little meat simply due to economic factors.)
Proper diet won’t prevent all cancer, but perhaps 10-20% of common cancer cases, such as prostate, breast, colorectal, and uterine cancer. A natural, nutrient-rich, mostly plant-based diet seems to bolster our defense against cancer.
Ms. Middelmann-Whitney is no wacko claiming you can cure your cancer with the right diet modifications. She writes, “…I do not advocate food as a cancer treatment once the disease has declared itself….”
She never brings it up herself, but I detect a streak of paleo diet advocacy in her. Several of her references are from Loren Cordain, one of the gurus of the modern paleo diet movement. She also mentions the ideas of Michael Pollan very favorably.
She’s not as high on whole grains as most of the other current nutrition writers. She points out that, calorie for calorie, whole grains are not as nutrient-rich as vegetables and fruits. Speaking of which, she notes that veggies generally have more nutrients than fruits. Furthermore, she says, grain-based flours probably contribute to overweight and obesity. She suggests that many people eat too many grains and would benefit by substituting more nutrient-rich foods, such as veggies and fruits.
Some interesting things I learned were 1) the 10 most dangerous foods to eat while driving, 2) the significance of organized religion in limiting meat consumption in some Mediterranean regions, 3) we probably eat too many omega-6 fatty acids, moving the omega-6/omega-3 ratio away from the ideal of 2:1 or 3:1, 4) one reason nitrites are added to processed meats is to create an pleasing red color (they impair bacterial growth, too), 5) fresh herbs are better added towards the end of cooking, whereas dried herbs can be added earlier, 6) 57% of calories in western societies are largely “empty calories:” refined sugar, flour, and industrially processed vegetable oils, and 7) refined sugar consumption in the U.S. was 11 lb (5 kg) per person in the 1830s, rising to 155 lb (70 kg) by 2000.
Any problems with the book? The font size is a bit small for me; if that worries you, get the Kindle edition and choose your size. She mentions that omega-6 and omega-3 fatty acids as “essential” fats. I bet she meant to say that linolenic and linoleic fatty acids are essential (our bodies can’t make them); linolenic happens to be an omega-3, linoleic is an omega-6. Reference #8 in chapter three is missing. She states that red and processed meats cause cancer, or at least are strongly linked; in my view, the studies are inconclusive. I’m not sure that cooking in or with polyunsaturated plant oils causes formation of free radicals that we need to worry about.
As would be expected, the author and I don’t see eye to eye on everything. For example, she worries about bisphenol-A, pesticide residue, saturated fat, excessive red meat consumption, and strongly prefers pastured beef and free-range chickens and eggs. I don’t worry. She also subscribes to the “precautionary principle.”
The author shares over 150 recipes to get you started on your road to cancer prevention. I easily found 15 I want to try. She covers all the bases on shopping for food, cooking, outfitting a basic kitchen, dining out, shopping on a strict budget, etc. Highly practical for beginning cooks. Numerous scientific references are listed for you skeptics.
I recommend this book to all adults with normal carbohydrate metabolism, particularly for those with a strong family history of cancer. But following the author’s recommendations would do more than lower your risk of cancer. You’d likely have a longer lifespan, lose some excess fat weight, and lower your risk of type 2 diabetes, dementia, heart disease, stroke, vision loss from macular degeneration, and obesity. Particularly compared to the standard American diet.
Disclosure: The author arranged a free copy of the book for me, otherwise I recieved nothing of value for writing this review.
Earlier this month, many folks made New Years’ resolutions to start exercising in conjunction with their other resolution to lose excess weight. I’ve got bad news for them.
Exercise is overrated as a pathway to major weight loss.
Sure, a physically inactive young man with only five or 10 pounds (2 to 4 kg) to lose might be able to do it simply by starting an exercise program. That doesn’t work nearly as well for women. The problem is that exercise stimulates appetite, so any calories burned by exercise tend to be counteracted by increased food consumption.On the other hand, exercise is particularly important for diabetics and prediabetics in two respects: 1) it helps in avoidance of overweight, especially after weight loss, and 2) it helps control blood sugar levels by improving insulin resistance, perhaps even bypassing it.
Even if it doesn’t help much with weight loss, regular physical activity has myriad general health benefits. First, let’s look at its effect on death rates.
EXERCISE PREVENTS DEATH
As many as 250,000 deaths per year in the United States (approximately 12% of the total) are attributable to a lack of regular physical activity. We know now that regular physical activity can prevent a significant number of these deaths.
Exercise induces metabolic changes that lessen the impact of, or prevent altogether, several major illnesses, such as high blood pressure, coronary artery disease, diabetes, and obesity. There are also psychological benefits. Even if you’re just interested in looking better, awareness of exercise’s other advantages can be motivational.
Exercise is defined as planned, structured, and repetitive bodily movement done to improve or maintain physical fitness.
Physical fitness is a set of attributes that relate to your ability to perform physical activity. These attributes include resting heart rate, blood pressure at rest and during exercise, lung capacity, body composition (weight in relation to height, percentage of body fat and muscle, bone structure), and aerobic power.
Aerobic power takes some explanation. Muscles perform their work by contracting, which shortens the muscles, pulling on attached tendons or bones. The resultant movement is physical activity. Muscle contraction requires energy, which is obtained from chemical reactions that use oxygen. Oxygen from the air we breathe is delivered to muscle tissue by the lungs, heart, and blood vessels. The ability of the cardiopulmonary system to transport oxygen from the atmosphere to the working muscles is called maximal oxygen uptake, or aerobic power. It’s the primary factor limiting performance of muscular activity.
Aerobic power is commonly measured by having a person perform progressively more difficult exercise on a treadmill or bicycle to the point of exhaustion. The treadmill test starts at a walking pace and gets faster and steeper every few minutes. The longer the subject can last on the treadmill, the greater his aerobic power. A large aerobic power is one of the most reliable indicators of good physical fitness. It’s cultivated through consistent, repetitive physical activity.
Physical Fitness Effect on Death Rates
Regular physical activity postpones death.
Higher levels of physical fitness are linked to lower rates of death primarily from cancer and cardiovascular disease (e.g., heart attacks and stroke). What’s more, moving from a lower to a higher level of fitness also prolongs life, even for people over 60.
Part 2 of this series will cover all the other health benefits of exercise. Part 3 will outline specific exercise recommendations, such as the type and duration of activity.
Italian researchers reviewed the medical/nutrition literature of the last three years and confirmed that the Mediterranean diet 1) reduces the risk of death, 2) reduces heart disease illness and death, 3) cuts the risk of getting or dying from cancer, and 4) diminishes the odds of developing dementia, Parkinsons disease, stroke, and mild cognitive impairment.
These same investigators published a similar meta-analysis in 2008, looking at 12 studies. Over the ensuing three years (as of June, 2010), seven new prospective cohort studies looked at the health benefits of the Mediterranean diet. The report at hand is a combination of all 19 studies, covering over 2,000,000 participants followed for four to 20 years. Nine of the 19 Mediterranean diet studies were done in Europe.
The newer studies, in particular, firmed up the diet’s protective effect against stroke, and added protection against mild cognitive impairment.
The Mediterranean diet: No other way of eating has so much scientific evidence that it’s healthy and worthy of adoption by the general population. Not the DASH diet, not the “prudent diet,” not the American Heart Association diet, not vegetarian diets, not vegan diets, not raw-food diets, not Esselstyne’s diet, not Ornish’s diet, not Atkins diet, not Oprah’s latest diet, not the Standard American Diet, not the . . . you name it.
Not even the Low-Carb Mediterranean Diet.
Just as important, the research shows you don’t have to go full-bore Mediterranean to gain a health and longevity benefit. Adopting just a couple Mediterranean diet features yeilds a modest but sigificant gain. For a list of Mediterranean diet components, visit Oldways or the Advanced Mediterranean Diet website.
Reference: Sofi, Francesco, et al. Accruing evidence about benefits of adherence to the Mediterranean diet on health: an updated systematic review and meta-analysis. American Journal of Clinical Nutrition, ePub ahead of print, September 1, 2010. doi: 10.3945/ajcn.2010.29673
A study in the current issue of the American Journal of Clinical Nutrition associates the Mediterranean diet with lower risk of breast cancer in postmenopausal women.
The data derive from the Greek portion of the massive EPIC study: European Prospective Investigation Into Cancer and nutrition. Investigators followed almost 15,000 women for 10 years. No protective effect was seen for premenopausal women eating Mediterranean-style. The study at hand adds to prior evidence that the Mediterranean diet seems to protect against cancer of the breast, prostate, uterus, and colon/rectum.
Reference: Trichopoulou, Antonia, et al. Conformity to traditional Mediterranean diet and breast cancer risk in the Greek EPIC (European Prospective Investigation into Cancer and nutrition) cohort. American Journal of Clinical Nutrition, published July 14, 2010. doi: 10.3945/ajcn.2010.29619