“How much sitting can a body take without hurting the heart? A meta-analysis of prospective cohort studies found a nonlinear association with cardiovascular disease (CVD), suggesting that 10 hours a day might be a critical threshold.”
Tag Archives: heart disease
For the bulk of my medical career, physicians thought that saturated fat caused heart disease, specifically coronary artery disease and heart attacks. Most doctors still think that. In 2009, I spent 80 hours reviewing the scientific literature supporting the saturated fat/heart disease connection. The evidence was very weak, if not nonexistent.
But what if you are already a heart disease patient? Would continuing saturated fat consumption have any effect on your longevity and risk of future heart attacks? If you already have coronary artery disease, Dr. Axel Sigurdsson says that ongoing saturated fat intake probably doesn’t matter, in terms of future cardiac events (like heart attacks) or risk of death from any cause.
Dr. Sigurdsson is a cardiologist in Iceland.
Some quotes from his blog:
For decades, cardiologists have advised patients with heart disease to restrict the intake of saturated fats and dietary cholesterol. Many patients still believe this to be the cornerstone of their lifestyle modification.
The main reason for avoiding saturated fats is the assumption that they adversely affect the lipid profile of our patients.
* * *
Recent studies suggest that the recommendation to avoid saturated fats may have been premature and not based on solid scientific evidence.
Now, a recently published Norwegian study shows that dietary intake of saturated fatty acids was not associated with risk of future events or death among patients with established coronary artery disease.
It is important to keep in mind that most of the patients were receiving secondary prevention drug therapy including aspirin, beta blockers and statins.
Anyhow, the results of the study certainly suggest that high intake of saturated fats is not a risk factor among patients with coronary heart disease receiving modern-day treatment.
These recent scientific data don’t imply that we should urge our patients to consume high amounts of saturated fats. They only tell us that there is no association and accordingly, restriction won’t help.
So, it’s certainly a lifeline for those who believe red meat, whole-fat milk, cheese, cream, butter and eggs can be a part of a healthy diet.
On the other hand we must realise that scientific studies often provide contradictory results. A US study published last year suggested that greater adherence to a low carbohydrate diet high in animal sources of fat and protein was associated with higher all-cause and cardiovascular mortality following acute heart attack.
It appears the jury is still out…
Here’s my review of The South Asian Health Solution: A culturally tailored guide to lose fat, increase energy, avoid disease by Ronesh Sinha, published in 2014.
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Dr. Sinha practices internal medicine in northern California (Silicon Valley) and has a large dose of South Asians in his clinic. “South Asia” usually encompasses India, Pakistan, Nepal, Bangladesh, Bhutan, Sri Lanka and Maldives. It is home to one fifth of the world’s population. This book pertains mostly to Indians, which is Dr. Sinha’s ethnicity. I live in the Pheonix, AZ, area and we have a fair number of Indian engineers and physicians.
WHY DO SOUTH ASIANS NEED THEIR OWN SPECIAL HEALTH GUIDE?
Because Dr. Sinha says they have unique genetic and cultural issues that predispose them to type 2 diabetes, abdominal obesity, coronary artery disease, high blood pressure, and adverse cholesterol numbers. For example, compared to natives who stay in their home countries, South Asian immigrants to the West have 3–4 times higher prevalence of diabetes, he says. Dr Sinha has a program that he’s convinced will prevent or forestall these medical problems in South Asians.
Dr. Sinha says South Asians eat too many carbohydrates and are too sedentary. Especially those who have moved to the West (e.g., US, UK, Europe, Canada). He notes that the core of the typical South Asian diet is flat breads, lentils, rice, fried crispy snacks (with heart-poisoning trans fats), culminating in 150–200 daily grams of carbohydrate more than he sees in other ethnics in California. Western fast foods, sodas, and sweets compound the problem.
He says “most South Asians are skinny-fat,” meaning skinny legs and arms but with a fat belly from visceral fat. This is also called sarcopenic obesity. The usual “healthy” body mass index (BMI) numbers don’t apply to Asians. The World Health Organisation classifies Asians as underweight if BMI is 18.4 or less, healthy at BMI of 18.5 to 13, overweight at BMI 23.1 to 25, and obese if BMi is over 25. These numbers are lower than those used for non-Asian populations.
Another issue in his South Asian patient population is vitamin D deficiency related to their dark skin (hence, less vitamin D production) and too much time indoors. He says vitamin D deficiency promotes inflammation and insulin resistance. More on this below.
Some South Asians have a K121Q gene mutation that causes insulin resistance, which in turn can cause disease. And whether it’s genetic or not (but I think it is), he says South Asians tend to have higher Lp(a) [aka lipoprotein(a)], which causes early and aggressive coronary artery disease. They also tend to have small dense LDL, leading to a lower-than-expected total cholesterol level which may be deceptively low.
Sinha notes a strong vegetarian preference in Indians but spends almost no time discussing it. From the book, I can’t tell if Indian vegetarians are lacto-ovo-vegetarians, pescetarians, or vegans. The author is not a vegetarian.
SINHA’S GRAND UNIFICATION THEORY OF DISEASE CAUSATION
So, South Asians, at least in the West, have a high-carb diet, are too sedentary, and have genetic tendencies to heart disease and diabetes. How do these factors cause disease? It’s all tied together with insulin resistance. Insulin is the main hormone that keeps our blood sugar from rising too high after we digest a meal. Insulin drives blood sugar into our body cells to be used as energy or stored as fat or glycogen. If our tissues have insulin resistance, blood sugar levels rise. As a compensatory effort, our pancreas excretes more insulin in to the blood stream than would normally be the case. Whether or not that eventually lowers blood sugar levels, the higher insulin levels themselves can cause toxicity. For example, higher insulin levels raise blood pressure, which damages the cells lining the insides of our arteries, leading to chronic inflammation and atherosclerosis (hardening of the arteries). Some of the arterial damage is mediated through small dense LDL cholesterols (aka type B LDL), which is promoted by high insulin levels (hyperinsulinemia). Insulin resistance also results in a defective and overactive immune system, which further promotes chronic inflammation. This inflammation is “…the root cause of almost every imaginable chronic disease…from heart attacks and strokes to Alzheimers Disease.”
Anyway, this is Dr. Sinha’s hypothesis, and there is some scientific evidence to support it. Sinha says that the concept of insulin resistance “weaves together virtually every chronic ailment currently afflicting South Asians.” That may be a bit hyperbolic: He carves out no exceptions for arthritis, asthma, eczema, migraines, glaucoma, macular degeneration, hearing loss, erectile dysfunction, hepatitis C, prostate enlargement, toenail fungus, or male-pattern baldness.
Dr. Sinha’s Grand Unification Theory of Disease Causation has some support among physicians and scientists, but is by no means universally accepted among them. As for myself, I think he’s over-simplifying (for his readership’s sake?) and getting a bit ahead of the science.
Most clinicians aren’t testing directly for insulin resistance. What are the indirect clues? Belly fat, low HDL cholesterol, high trigylcerides, high blood pressure, prediabetes, and type 2 diabetes. These are components of the metabolic syndrome. Not everybody with one or more of these factors has insulin resistance but many do.
WHAT’S HIS PROGRAM?
If Sinha is correct, the South Asian Health Solution is a “low-insulin lifestyle” achieved through carbohydrate-reduced eating, exercise, and avoidance or resolution of belly fat. These help improve all components of the aforementioned metabolic syndrome. The backbone of the plan is carbohydrate restriction. For low-carb eating, avoid wheat bread and Indian flat breads (e.g., chapatis, naans, parathas, puris, phulkas), aloo (primarily potatoes and starchy vegetables), rice and other grains, beans, and sugar. Keep track of your net carbohydrates (he likes FitnessPal.com, which includes South Asian foods).
If you need to burn off body fat, limit carbs to 50–100 grams/day (digestible or net carbs, I assume). Aim for 100–150 grams/day to maintain health and weight loss.
You might be able to add “safe starches” later: white rice, potatoes. To replace your Indian flat breads, learn how to make them with substitutes for wheat flour: coconut flour or almond flour (no skins) or almond meal (skin included). Recipe on page 347. Rice alternatives are cauliflower “rice,” shredded cabbage, broccoli slaw, chopped broccoli, and chopped carrots.
He likes ghee, extra virgin olive oil, coconut oil, and butter. Avoid high omega-6 fatty acid consumption, as in vegetable oils. Of course, avoid trans fats. Good fats are saturated, monousaturated, and omega-3s.
He provides a few low-carb recipes, surprisingly without specific carb counts: chapatis, microwave bread, cauliflower pizza, coconut cauliflower rice, shredded cabbage sabji, gajar halwa (carrot pudding), and coconut ladoo.
Dr. Sinha doesn’t provide a comprehensive meal plan. He trusts his California South Asians to figure out how and what to eat. They’re smarter than average (he never says that, but that’s been my experience with South Asians in my world).
Dr. Sinha is also a huge proponent of exercise. He’ll tell you about squats, lunges, planks, burpees, yoga, and Tabata intervals. He agrees with me and Franziska Spritzler that “physical activity is the most effective fountain of youth available.”
I skipped some of the chapters due to lack of time and interest: women’s issues (e.g., pregnancy, polycystic ovary syndrome, post-partum depression, osteoporosis), childhood, fatigue and stress management, and anti-aging.
- He likes high-sensitivity CRP testing.
- His metabolic goals for South Asians are: 1) keep waist circumference under 35 inches (90 cm) in men, under 31 inches (80 cm) in women, 2) keep triglycerides under 100 mg/dl (1.13 mmol/l), 3) keep HDL cholesterol over 40 mg/dl (1.03 mmol/l) for men, and above 50 mg/dl (1.29 mmol/l) for women, 4) keep systolic blood pressure 120 or less, and diastolic pressure 80 or less, 5) keep fasting blood sugar under 100 mg/dl (5.6 mmol/l) and hemoglobin A1c under 5.7%, and 6) keep hs-CRP under 1.0 mg/dl.
- He says HDL cholesterol helps reduce insulin resistance via apoprotein A-1 (apo A-1), which increases glucose uptake by cells.
- He likes to follow the triglyceride/HDL ratio. If under 3, it means low risk of insulin resistance being present.
- He likes to follow total cholesterol/HDL cholesterol ratio: ideal is under 3.5.
- Statins are way over-used.
- Ignore total cholesterol level by itself.
- Stress control and sleep are important.
- The author had some metabolic syndrome components: high triglycerides, low HDL cholesterol, and type B LDL (small, dense particles).
- He dislikes the usual-recommended low-fat, low-cholesterol diet.
- 4 tbsp (60 ml) of extra virgin olive oil daily seems to lower blood pressure.
- Magnesium supplementation may lower blood pressure.
- The liver stores about 100 grams of glycogen and muscles store 300–500 grams.
- Vanaspati is a “cheap ghee substitute” made from vegetable oil and widely used in Indian restaurants and many Indian processed foods. Avoid it since it’s a source of trans fats.
- Aloo sabji is a potato dish.
- Traditional Indian herbs/spices include turmeric, cardamon, ginger, and cilantro.
- Find an Indian medication guide at http://www.medguideindia.com/show_brand.php.
- Coconut milk is a traditional fat in India.
- Curry, curry, curry.
- Non-alcoholic steatohepatitis (NASH) is quite common in South Asians, seemingly linked to visceral (abdominal) obesity and insulin resistance related to carbohydrates.
- The book has no specific focus on diabetes.
THUMBS UP OR DOWN?
Overall, I like many of Dr. Sinha’s ideas. They seem to be supported by his experience with his own patients. I trust him. I bet many South Asians and non-Asians eating the Standard American Diet would see improved health by following his low-carb, physically active program.
Medical student Kris Gunnars has an article at Business Insider, of all places, that shows graphically many of the major U.S. dietary changes of the last hundred years. In this case, transmogrification may be a better term than mere “changes.” Much of the Western world has evolved in similar fashion.
You need to read the article and ponder the graphs if you question why we have so much obesity, type 2 diabetes, heart disease, hypertension, and perhaps cancer. You’ll see dramatic increases in consumption of added sugars, industrial seed oils (esp. soybean), soda pop and fruit juice (added sugar!), total calories, and fast food. You’ll see how much we’ve increased dining away from home. Butter consumption is down drastically, but doesn’t seem to have done us much good, if any.
There’s fairly good evidence that coronary artery disease (CAD) the cause of most heart attacks) was very prominent between 1960 to 2000 or so, but it’s been tapering off in recent years and didn’t seem to be very common 100 years ago. Understand that you can have it for 20 years or more before you ever have symptoms (angina) or a heart attack from it. In fact, the disease probably starts in childhood. I’ve always wondered about the cause of the CAD prevalence trends, and wondered specifically how much of the long-term trend was related to trans-fat consumption. But I’ve never been able to find good data on trans-fat consumption. Kris came up with a chart of margarine consumption, which may be a good proxy for trans-fats. Another of his charts includes shortening, a rich source of trans-fats and probably also a good proxy. I remember growing up in the 1960s that we always had a 1/2 gallon tin can of Crisco hydrogenated fat in the cupboard. Shortening consumption increased dramatically from 1955 until dropping like a rock around 2000.
The timeline curves for trans-fat consumption (by proxy) and prevalence of coronary heart disease seem to match up fairly well, considering a 20 year lag. In the early 1990s, we started cutting back on trans-fats, and here we are now with lower mortality and morbidity from coronary artery disease. (CAD is very complex; lower rates of smoking surely explain some of the recent trend.)
Read the whole enchilada. Very impressive. Highly recommended.
The largest benefits were seen in people who ate seven or more servings of fruits and vegetables a day compared with those who ate less than one serving, with the higher level of consumption associated with significantly lower all-cause mortality (hazard ratio 0.67; 95% CI 0.58-0.78), lead researcher Oyinlola Oyebode of University College London, and colleagues, reported online in the Journal of Epidemiology and Community Health.
The population under study was English. In addition to lower risk of death, the heavy fruit and vegetable consumers had lower rates of cancer and cardiovascular disease. Click for the actual research report.
If seven servings a day seems like a lot, note that a typical serving is only half a cup. You’ll get those with the Low-Carb Mediterranean Diet.
Steve Parker, M.D.
Japanese researchers say low-carb diets are causing premature death. I’m skeptical.
The potentially healthful side effects linked to low-carb eating include reduced weight, higher HDL cholesterol, and lower triglycerides and blood pressure. The Japanese investigators wondered if the improved cardiovascular risk factors seen with low-carb diets actually translate into less heart disease and death.
How Was the Study At Hand Done?
The best way to test long-term health effects of a low-carb diet (or any diet) is to do a randomized controlled trial. You take 20,000 healthy and very similar people—not rodents—and randomize half of them to follow a specific low-carb diet while the other half all eat a standard or control diet. Teach them how to eat, make damn sure they do it, and monitor their health for five, 10, or 20 years. This has never been, and never will be, done in humans. The Nazis may have done it, but it’s not published. In the old days, we could do this study on inmates of insane asylums or prisons.
What we have instead are observational studies in which people voluntarily choose what they’re eating, and we assume they keep eating that way for five or 10+ years. You also assume that folks who choose low-carb diets are very similar to other people at the outset. You depend on regular people to accurately report what and how much they’re eating. You can then estimate how much of their diet is derived from carbohydrate and other macronutrients (protein and fat), then compare health outcomes of those who were in the top 10% of carb eaters with those in the bottom 10%. (We’ve made a lot of assumptions, perhaps too many.)
Of the observational studies the authors reviewed, the majority of the study participants were from the U.S. or Sweden. So any true conclusions may not apply to you if you’re not in those countries. In looking for articles, they found no randomized controlled trials.
The observational studies estimated carb consumption at the outset, but few ever re-checked to see if participants changed their diets. That alone is a problem. I don’t know about you, but I’ve had significant changes in my diet depending on when I was in college and med school, when I was a bachelor versus married, when my income was higher or lower, and when I had young children versus teenagers. But maybe that’s just me.
The researchers looked at all-cause mortality, deaths from cardiovascular disease, and incidence of cardiovascular disease. They don’t bother to define cardiovascular disease. I assume heart attack, strokes, and peripheral vascular disease. (But aren’t aneurysms, deep vein thrombosis, and pulmonary embolism vascular diseases, too?) Wouldn’t you think they’d carefully define their end-points? I would. Since they were going to all this trouble, why not look at cancer deaths, too?
What Did the Investigators Conclude?
Very low-carbohydrate dieters had a 30% higher risk of death from any cause (aka all-cause mortality) compared to very high-carb eaters. The risk of cardiovascular disease incidence or death were not linked with low-carb diets. Nor did they find protection against cardiovascular disease.
Finally, “Given the facts that low-carbohydrate diets are likely unsafe and that calorie restriction has been demonstrated to be effective in weight loss regardless of nutritional composition, it would be prudent not to recommend low-carbohydrate diets for the time being.”
If Low-Carb Dieters Die Prematurely, What Are They Dying From?
The top four causes of death in the U.S. in 2011, in order, are:
- heart attacks
- chronic lower respiratory tract disease
You’ll note that two of those are cardiovascular disease (heart attacks and stroke). So if low-carb diets promote premature death, it’s from cancer, chronic lung disease, or myriad other possibilities. Seventy-five percent of Americans die from one of the top 10 causes. Causes five through 10 are:
- Alzheimer disease
- flu and pneumonia
- kidney disease
Problem is, no one has ever linked low-carb diets to higher risk of death from any specific disease, whether or not in the top ten. Our researchers don’t mention that. That’s one reason I’m very skeptical about their conclusion. If you’re telling me low-carb diets cause premature death, tell me the cause of death.
Another frustration of mine with this report is that they never specify how many carbohydrates are in this lethal low-carb diet. Is it 20 grams, 100, 150? The typical American eats 250-300 grams of carb a day. If you’re going to sound the alarm against low-carb diets, you need to specify the lowest safe daily carb intake.
For most of my career—like most physicians—I’ve been wary of low-carb diets causing cardiovascular disease. That’s because they can be relatively high in total fat and saturated fat. In 2009, however, I did my own review of the scientific literature and found little evidence of fats causing cardiovascular disease.
If you’re looking for a reason to avoid low-carb diets, you can cite this study and its finding of premature death. I’m not convinced. I’ll turn it around on you and note this study found no evidence that low-carb diets cause cardiovascular disease. The risk of cardiovascular disease had been the traditional reason for physicians to recommend against low-carb diets.
Reference: Noto, Hiroshi et al. Low-Carbohydrate diets and all-cause mortality: A systematic review and meta-analysis of observational studies. PLoS One, 2013; 8(1): e55050
Conner Middelmann-Whitney explains in her recent post at Psychology Today. In a nutshell, they are linked to longer life and better health. For example:
In the largest study of its kind, Harvard scientists found that people who ate a handful of nuts every day were 20% less likely to die from any cause over a 30-year period than those who didn’t consume nuts. The study also found that regular nut-eaters were leaner than those who didn’t eat nuts, a finding that should calm any fears that eating nuts will make you gain weight.
The report also looked at the protective effect on specific causes of death. “The most obvious benefit was a reduction of 29% in deaths from heart disease—the major killer of people in America,” according to Charles S. Fuchs, director of the Gastrointestinal Cancer Treatment Center at Dana-Farber, the senior author of the report and a professor of medicine at Harvard Medical School. “But we also saw a significant reduction—11% —in the risk of dying from cancer,” added Fuchs.
Walnuts seem to have the lowest omega-6/omega-3 fatty acid ratio of all the common nuts. That may make them the healthiest nut. The jury is still out. Macadamia nuts also have a good ratio. Paleo dieters focus on cutting out omega-6s and increasing omega-3s. Julianne Taylor has a great post on how to do that with a variety of foods, not just nuts.