Category Archives: Nutrition

Medical ecology: tending the microbiome

Today, the Obama administration announces the new National Microbiome Initiative, intended to create scientific tools, discoveries and training techniques related to the human microbiome, the 100 trillion microbes that live in the human body. Tending the human microbiome may help in the treatment of infections, as well as disorders that would seem unrelated to microbes, including obesity and diabetes.

The microbiome represents the only organ that can be replaced without surgery,” said Jo Handelsman, a microbiologist at the White House. “Just by eating differently, taking drugs, exercising and other things, you can have fairly immediate effects on your microbiome and your health, if we only knew how.”

Microbiome research also has important public health implications. New research, for instance, suggests that much of the world’s childhood malnutrition arises not from a lack of food, but from problems with children’s intestinal microbiomes caused by poor sanitation.India-Sanitation-web-Artboard_1

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Avoid peanut allergy by early introduction of peanuts

A study released today in the New England Journal of Medicine showed that giving infants small amounts of peanut butter in their first year of life substantially reduced the prevalence of peanut allergy when compared to infants who avoided peanuts for their first year. The investigators found that the safeguard lasted for a year after the children stopped consuming peanut protein.

Overall, after the introduction of peanuts in the first year of life, peanut consumption for the following 4 years, and a year of abstinence from peanuts, the peanut-consumption group had a prevalence of peanut allergy that was 74% lower than the prevalence in the peanut-avoidance group, a finding that shows unresponsiveness to peanut after a long period (12 months) of peanut avoidance.

Screen Shot 2016-03-04 at 2.41.36 PMIn a second study also released today in the same journal, the investigators tried to repeat those findings with other foods that commonly lead to allergies in children, including milk, eggs, fish, wheat and sesame. They again showed that the approach might work, but because so few families stuck to the difficult feeding regimen, the outcome was not conclusive

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Coffee: to drink or not to drink

According to the U.S. Food and Drug Administration, 90% of people worldwide, and 80% in the US, consume caffeine in some form every day. The average adult has an intake of about 200 milligrams, or roughly one cup of coffee per day.

As one of those few non-coffee-drinking adults–probably rarer still among emergency medicine providers–I was intrigued by  today’s New York Times review of the risks and benefits of coffee consumption. Given that most evidence is observational, not based on randomized trials, it is hard to draw causal relationships between coffee intake and various outcomes. Nonetheless, the accumulation of evidence led the U.S.D.A. to address coffee in its latest nutritional guidelines, guidelines I have discussed before. On coffee, the guidelines state:

Currently, strong evidence shows that consumption of coffee within the moderate range (3 to 5 cups per day or up to 400 mg/d caffeine) is not associated with increased long-term health risks among healthy individuals. In fact, consistent evidence indicates that coffee consumption is associated with reduced risk of type 2 diabetes and cardiovascular disease in adults. Moreover, moderate evidence shows a protective association between caffeine intake and risk of  Parkinson’s disease. Therefore, moderate coffee consumption can be incorporated into a healthy  dietary pattern, along with other healthful behaviors. However, it should be noted that coffee as  it is normally consumed can contain added calories from cream, milk, and added sugars. Care should be taken to minimize the amount of calories from added sugars and high-fat dairy or dairy substitutes added to coffee.

After reviewing the evidence (Chapter 5), the report concludes that those who are not consuming coffee should not commence coffee consumption for health benefits alone.

The Well blog presents potential benefits as well as risks of moderate coffee consumption, and draws the same conclusion as the USDA guidelines.

“It’s one thing to say it’s safe,” said Dr. Rob van Dam, an adjunct associate professor of nutrition and epidemiology at Harvard University. “It’s another thing to recommend it as a medical choice even though people don’t like it and they’d have to make an effort to adopt it. We’d need a different level of evidence to recommend it to people.”

The experts’ hesitance to recommend changing coffee-drinking behavior is not surprising, given the “level of evidence”: the evidence pro- and con-coffee is epidemiologic, that is, based on observations of patterns.

The Incidental Economist, in the Times’ Upshot column, takes this perspective slightly further, noting that the evidence shows it is time to move away from traditional admonitions urging all coffee-drinkers to cut down.

It’s a completely reasonable addition to a healthy diet, with more potential benefits seen in research than almost any other beverage we’re consuming.

On the other side–exemplified by a Forbes article “Caffeine: The Silent Killer of Success”, coffee still has addictive properties and needs to be used with caution, if at all.

Personalized preventive medicine

Much research and media attention have focused on personalized medicine.  The National Cancer Institute defines personalized medicine as “a form of medicine that uses information about a person’s genes, proteins, and environment to prevent, diagnose, and treat disease.”  Although this definition includes prevention, much of the focus of personalized medicine has been on treatments, with a focus on genetics as the key determinants of a patient’s predicted response.  President Obama’s Precision Medicine Initiative, for example, which this month is 12 months old, focuses on tailoring treatments to the individual, with little mention of personalizing preventive medicine modalities.

Per the CDC’s Preventive Care site, preventive care includes both health promotion and disease screening.

  • Health promotion includes proper immunizations, managing one’s weight, being physically active, eating a healthy diet, not smoking, drinking moderate amounts of alcohol, wearing seat-belts/helmets, getting enough rest, surrounding oneself with family and friends, driving safely, managing stress, and, in general, living what most would agree is a healthy lifestyle. These are activities that often do not require medical personnel–they are often individually guided, or can be policy-related, such through laws requiring seatbelt use, taxing cigarettes, and restricting the availability of sugary drinks at schools.
  • Disease screening includes health services like mammograms, colonoscopies, Pap tests and regular tests of blood pressure and cholesterol.  These services generally involve medical personnel.

The CDC site also includes a tool you can use to identify the recommended disease screening services by age and gender, reflecting a basic level of preventive care personalization by these two factors.  A Health Affairs article provides a more detailed overview of preventive health modalities and the potential cost-benefit for them.

PrintA recent NY Times post highlights the value of personalized preventive medicine:  it summarizes recent studies that show the way we absorb and metabolize various foods is highly variable and thus dietary advice is not one-size-fits-all.  Some of the factors that determine an individual’s response to various foods include demographics, genetic makeup, gut bacteria, body type, medications, family history, lifestyle, and chemical exposures. A video summary of one study featured, “Personalized Nutrition by Prediction of Glycemic Responses” is available here.  Although recently we have learned more about the ideal “dosing” of exercise for the population, the recommendations are not personalized.

One of the more controversial attempts at personalizing preventive care was the U.S. Preventive Services Task Force guidelines on mammography.  After review of existing research, the Task Force decided against recommending mammography for some women in their 40s.  The personalized preventive medicine approach also took into account family history: the Task Force recommended that women with mothers or sisters with a history of breast cancer may benefit more from screening in their 40s.mh-strat-determinants-of-health-en

2015 Dietary Guidelines: a gallon of lobbying and a pinch of nutrition science?

New federal dietary guidelines issued last week by the Agriculture and Health and Human Services Departments, urge Americans to drastically cut back on sugar, and for the first time have singled out teenage boys and men for eating too much meat, chicken and eggs.

The biggest change is restricting added sugar: Americans consume up to 22 teaspoons a day. To meet the new 10 percent target, they’d need to cut their sugar intake by nearly half — to no more than 12 teaspoons a day on a 2,000-calorie daily diet.a59d73eee7329639a0492a8acc71f3608adc7cfc

Two surprises in the guidelines were both related to protein:

  1. The recommendation that men and boys “reduce their overall intake of protein foods” such as meat, poultry and eggs and add more vegetables to their diets.gr-meat-consumption
  2. The absence of a recommended dietary limit for red or processed meat, even though the Guidelines Advisory Committee recommended one be put in place after a controversial World Health Organization report declared that processed meats cause cancer, and red meats likely cause cancer.

Per the New York Times and NPR, the absence of a recommendation on meat consumption is related to lobbying from the meat industry (quotation from NY Times):

Last year, an advisory committee of nutrition experts assembled by the government recommended that the dietary guidelines encourage all Americans to consume more plant-based foods and less meat to help promote environmentally sustainable eating habits. That suggestion elicited intense lobbying and criticism from the food and meat industries, leading to a congressional hearing on the topic last year. In December, Congress passed a spending bill that contained a provision calling for a review of the dietary guidelines by the National Academy of Medicine and restricting the scope of the guidelines to nutrition, which essentially eliminated the advice about following an environmentally-sustainable diet.

The report also excludes other notable recommendations made by the Dietary Guidelines advisory panel that reviewed the latest nutrition science. For instance, the advisory committee had recommended including sustainability as a factor in making food choices. But administration officials nixed that idea.dietary-guidelines_larger_custom-54044ab72226fe0978a0b6aee5ed589c44fbd20b-s600-c85

The Dietary Guidelines have implications for federal nutrition policy, influencing everything from the national school lunch program to the advice you get at the doctor’s office.

A year ago, the New York Times ran a great review of the science behind the dietary guideline changes recommended by the Dietary Guidelines Advisory Committee.

What do you think of the guidelines? How do they impact you?

Limerick version of In Defense of Food

This poem is inspired by Michael Pollan’s PBS documentary In Defense of Food, available here for free viewing until the end of the month:
The wisdom Michael Pollan incants–
Eat food, not too much, mostly plants—
Is simple declared
Yet we’re easily ensnared
By the food industry’s science-y dance.
So here are some other wise rules
That Pollan provides as tools
To help navigate
Pseudo-research-y bait
Including that from some prominent schools.
First, avoid what would seem unreal
To your great grandma as a true meal
Those with ingredients covert
Like Ho-Ho’s and Go-Gurt–
Food “products” that over make us keel.
Next, avoid added forms of fructose
It’s in many things—often high-dose
Such as soda and chips,
Fat-free yogurt, pretzel sticks,
Even “healthy” instant cups of oats!
Third, avoid the lure of foods that are cheap
These bargains cause our waistlines to creep
Buying lower quality fare
Costs us more on healthcare
And can hurt our planet’s upkeep.
Fourth, avoid health claims on the label
Whole Grain Lucky Charms are a fable
In fact, the healthiest (the plants)
Lack all label-based rants
Like “natural” and other finagles.
Last: buy local, in-season when you can
Or grow your own—what a plan!
At home, cook and enjoy
Sharing meals brings more joy
And may even increase your lifespan!
Check out my other medical verse here.

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Will prevention ever be sexy?

As a pediatric emergency medicine provider, many of the reasons patients show up in the Emergency Department are related to symptoms–a fever, cough, rash, ache, nausea, runny nose, diarrhea, etc.  What is this causing it? What will make it go away as soon as possible?

A commentary on NPR’s Shots series notes that, often, despite our best medical evidence and diagnostic technology, “what we doctors do is more about making educated guesses”.

What causes a child’s ear infection or pneumonia? Mostly we guess at what’s causing it and treat accordingly. When I explain the uncertainty involved in various options, this is often puzzling and frustrating to patient families. They want certainty–they want their child feeling all better. Who wouldn’t?

In contrast to the uncertainty around whether to treat an ear infection with antibiotics, we have far better evidence supporting preventive health. Although I have focused a lot on preventive vaccines lately, other aspects of preventive medicine are supported by similarly large bodies of  epidemiological research. Most of prevention is fairly straightforward, rather boring, and lacks the appeal of a quick fix (gluten  free donuts!)

Summarizing, here is the Shots commentary’s list:

  • Get enough sleep.
  • Move your body throughout the day.
  • Eat well — a healthy assortment of unprocessed foods. Mostly plants, and not too much. (An idea popularized by author Michael Pollan, whose movie can be seen free for the next month here).
  • Interact socially. Isolation is not good for the body, soul or mind.
  • Take some time to reflect on what you are grateful for.

These life habits are key–so much so that some medical schools are even teaching their students to cook so they can better support their patient’s healthy eating choices.

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I append this list with the also-important (and even less sexy) screening recommendations of the US Preventive Services Task Force.