nutrition

Longevity – Health Span vs Life Span

Longevity is the newest health buzzword. There are an increasing number of so-called longevity experts. They say, just read my book and follow my instructions and you can live past 100 years. Some of these “experts” focus on health span. They say follow my instructions and you will stay healthy and die suddenly at an advanced age. As of 4/21/2024 there are 34 books on longevity listed on Amazon.

In this post I will do my best to distinguish the hype from the science with regard to living a long and healthy life.

Hype

  1. Calorie restricted diets – Some people have extrapolated mouse and rat experiments that show that animals fed restricted calorie diets live a lot longer than animals fed a normal diet. There is not one shred of evidence that this works with humans, and is more likely to lead to diseases of malnourishment.
  2. Nutrtional supplements – Recommendations range from vitamins, to protein powder, to collagen powder, to herbal preparations, to encapsulated fruits and vegetables. There is absolutely no evidence that any of these things or any other supplements including multivitamins work to extend your life. Anecdotal reports of feeling better on these supplements are almost certainly a placebo effect
  3. Anti-aging medicines – reservetrol, metformin, rapamycin have all been shown to prolong life in some experimental animals. In humans Metformin and reservetrol decrease the ability to exercise and rapamycin suppresses the immune system. There is no evidence whatever that these compounds increase life or health span in humans.
  4. Extensive lab tests – Other than lipid (cholesterol) tests, there is no evidence that otherwise healthy non-obese people benefit from any blood tests. More about screening tests later.
  5. Imaging tests – One of the most popular longevity “experts” ,Dr. Peter Attia, recommends full body MRI scans for his patients. Imaging tests in people who have no symptoms are much more likely to lead to over diagnosis and unnecessary treatment than to find things that really need to be treated,
  6. Very intense exercise regimens – The only thing very intense exercise regimens accomplish that moderate exercise regimens do not is that the intense regimens are more likely to cause injury.

Science

Genetics

Up until into the 80’s, lifestyle is the major contributor to healthy aging. There are some people, however who remain healthy well into their 90’s and a few to past 100. Genetics is the main contributor to these “super centenarians.” There is not a single or even a few aging genes. Super aging is caused by hundreds of genetic variants called SNP’s (single nucleotide polymorphisms). We cannot alter our genes (yet), so there are no lifestyle changes you can make in order to live to 100 if you don’t have the rare combination of all these genetic variants.

That is not to say that lifestyle is not important to healthy aging. In the US, the average person’s last birthday in good health is age 65! Lifestyle changes will almost certainly help you do better than that.

Exercise

Regular exercise decreases your risk of chronic disease and therefore increases your chance of living healthier longer. To accomplish the maximum health benefit the CDC recommends 150 minutes of moderate exercise per week. Brisk walking or cycling at a moderate pace on level ground would qualify. If you choose high intensity exercise like jogging or running or high intensity cycling, you only need to do 75 minutes a week according to the CDC. The CDC also recommends activity to strengthen your muscles two days a week. For a population of adults doing this exercise regimen the risk of death is decreased by 17%. This regimen decreases the risk of heart disease, diabetes, certain cancers and decreases the risk of hospitalization or death from infectious diseases like COVID, flu and pneumonia. This regimen also increases bone and muscle strength and thus decreases the risk of falls and fractures. This exercise regimen also helps maintain a healthy weight.

Any amount of walking or activity decreases risk somewhat. The CDC recommended regimen decreases risk the most.

Nutrition

Eat mostly unprocessed foods and avoid ultra-processed foods. The best way to identify ultra-processed foods is to look at the ingredients label. If there are more than four ingredients, and/or if there are some you don’t recognize, then put that food back on the shelf. It is best to keep nutrition advice simple. The most concise recommendation I know comes from author Michael Pollan. “Eat food (food is anything your grandmother would have recognized as food), not too much, mostly plants.” I can’t do much better than that. Most of the evidence about the beneficial effects of good nutrition come from studies of the Mediterranean style diet. The Mediterranean diet adheres to Michal Pollan’s advice. It has lots of fruits, vegetables, fish, olive oil and very little meat. Adherence to this type of diet showed a 46% increase in living healthfully until 70 or greater.

Social Connectedness

The CDC defines social connectedness as the degree to which people have and perceive a desired number, quality, and diversity of relationships that create a sense of belonging, and being cared for, valued, and supported. An analysis of multiple studies showed that high social connectedness as defined above decreases the risk of premature death by 50%! High social connectedness also decreases the risk of heart disease, stroke and dementia.

Social Determinants of Health

The main reason that the US average health span is 65 years is the tremendous inequity of resources in the US. People who live in substandard housing (or no housing at all) do not have the opportunity or resources to do all of the things above that tend to extend life. That is why life expectancy at birth is related to zip code more than any other factor. My feeling is that we should expend our resources working on improving health equity, which will increase both life and health span for everyone rather than focusing on helping wealthy people live to 100.

Screening Tests

There are a few screening tests recommended by the US Preventive Care Task Force for healthy people. These tests are meant to find disease, especially cancer early so it can be more successfully treated and thus prolong healthy life. The absolute risk reduction of death for these tests is small, most around 1%, but that ends up saving a lot of people when you apply it to the whole US population. The recommended screening tests are listed below.

  1. Mammograms for women beginning at age 50. Recommended every two years. Absolute risk reduction about 1%.
  2. Pap Smears beginning at age 21 every 3 years through age 29 and then every 5 years from age 30 to 65. The absolute death risk reduction is .0009%, which means your would need to do pap smears on 11140 women to prevent one death from cervical cancer.
  3. Colorectal cancer screening. There are three different tests: colonoscopy, the most invasive (recommended every 10 years), Cologuard (a stool sent to a lab in a box recommended every 3 years) and fecal immunochemical test (done on a stool sample and either tested at home or sent to lab recommended every year). All three tests reduce deaths from colon cancer with an absolute risk reduction of around 0.6%. Only colonoscopy can prevent some cancers by removing precancerous polyps.

Vaccines

There is no question that vaccines save lives by preventing some serious life threatening diseases, or making them less severe. Vaccines are especially important for infants and children, who are most at risk from the infectious diseases prevented by vaccines. Childhood vaccines prevent diptheria, whooping cough, tetanus, measles, mumps, rubella, polio, rotavirus (which causes severe diarrhea and dehydration in infants), hemophilus influenza (which caused joint infections and meningitis), hepatitis b, RSV (which causes severe respiratory illness), pneumonia caused by strep (the most common kind of bacterial pnuemonia), COVID (also for adults), meningitis, chicken pox, and HPV (the virus that causes cervical cancer in women).

Adults can get any of these vaccines, but also a vaccine to prevent shingles.

Bottom Line

Living in good health to past 100 depends on genetics, not lifestyle. Many things recommended by so called longevity experts do nothing to prolong life and may increase risk. There are a number of lifestyle changes including exercise, good nutrition, social connectedness, certain screening tests and vaccines that increase you chances of remaining healthy well into your eighties. The main cause of early death in the US is poverty, homelessness and systemic racism. Addressing these inequities is a lot more important than helping wealthy people try to live to 100.

Sugar and High Fructose Corn Syrup

Sugar (actually anything that tastes sweet) releases dopamine to pleasure centers in the brain. These are the same centers that get activated by things like cocaine, heroin, methamphetamine and alcohol. Anything that activates the pleasure centers has the potential to be addictive. Most experts agree that sugar (and high fructose corn syrup, which tastes even sweeter) are addictive. Here is a link to an article from Healthline.org that gives further information about the addictiveness of sugar: Is Sugar an Addictive Drug?

Our hunter gatherer ancestors did not have to worry about addiction, because things that tasted sweet were rare and seasonal. In our society, sweet tasting food is everywhere and easily available. That, of course, is a recipe for addiction.

Sucrose and fructose

The vast majority of the sweetener that is added to processed foods (or that we add on purpose) is either sugar (sucrose) or high fructose corn syrup. Sucrose is also what makes honey and maple syrup taste sweet. High fructose corn syrup tastes sweeter than sucrose and is also considerably cheaper. That is why it is so prevalent in processed foods.

Americans eat an average of 37 pounds per person per year of high fructose corn syrup and 52 pounds of sugar per person per year. This is a huge health problem as I will outline below.

Sucrose is broken down in the body to glucose and fructose. Glucose is used as fuel for the body and especially the brain. If we take in more glucose than we need immediately for fuel the excess gets stored. Some is stored in the liver as glycogen. Glycogen gives us a ready energy source and is easily converted back to glucose. Any extra glucose is used to make triglycerides, which are then stored as fat. It is much harder to mobilize fat from storage.

Fructose is a much bigger problem. Fructose can only be broken down in the liver. Fructose is found in small quantities in fresh fruits, but eating sugar and/or especially high fructose corn syrup produces more fructose than the liver can handle. This excess fructose causes fat deposits in the liver (called fatty liver disease). The medical term is NAFLD (non alcoholic fatty liver disease). More than 25% of the population in the United States has NAFLD. The excess fat in the liver causes inflammation and twenty to thirty percent of people with NAFLD progress to something called NASH (non alcoholic steatohepatitis). Between five and twelve percent of people with NASH progress to cirrhosis of the liver. NASH is now a much more common cause of cirrhosis of the liver than alcoholism! Even more disturbing is that 2.6% of people with cirrhosis from NASH develop cancer of the liver.

Lets do a little math. If we randomly choose 1000 adults in the United States, 250 of them will have fatty liver (NAFLD). That is one in every four people. Of that 250, 75 will develop inflammation of the liver (NASH). Of that 75, 9 will develop cirrhosis of the liver. Think about those numbers for a minute. Eating foods with added sugar or especially high fructose corn syrup causes cirrhosis of the liver in 9 out of every thousand adults in the United States. If we choose a hundred people with cirrhosis from NASH, three of them will get liver cancer. That is a huge burden of disease! If you want to read more, here is a link to the NIH: How high fructose intake may trigger fatty liver disease

How to avoid high fructose corn syrup

You should look at the labels of everything you buy in the grocery store or convenience store. Foods that contain high fructose corn syrup have to list it on the label. You would be surprised at the number of foods that have high fructose corn syrup added. Here is a link to a web page that lists 23 different foods that often have high fructose corn syrup added: 23 Surprising Foods That Contain High Fructose Corn Syrup. If you stay away from the middle aisles in the grocery store as much as you can, then you will avoid most of these foods. I would strongly suggest that you not buy anything that contains high fructose corn syrup.

What about sugar, honey and maple syrup?

Sugar, honey and maple syrup are all sweet because they are or contain sucrose. Once again, the operative word is moderation. It is not going to damage your health to have an occasional cookie, piece of cake, piece of pie or small bowl of ice cream. It should be less than once a week, though. You have to be vigilant not to buy food that has ”stealth” sweeteners added. Soft drinks are the worst. Mountain Dew, for example has 46 grams of sugar per can. It is best to avoid soft drinks altogether. For other grocery items I can’t emphasize enough to read the labels.

Bottom Line

Sugar and high fructose corn syrup are addictive. In excess both of them are toxic to the liver and can lead to cirrhosis of the liver and liver cancer. They also make people fatter with all the health risks of obesity. Read the labels when you grocery shop and avoid foods containing high fructose corn syrup. Limit foods containing sugar, honey or maple syrup to less than once a week.

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