high-fat diet
Americans Are Still Eating Too Much Added Sugar, Fat
Posted on by Dr. Francis Collins
Most of us know one of the best health moves we can make is to skip the junk food and eat a nutritious, well-balanced diet. But how are we doing at putting that knowledge into action? Not so great, according to a new analysis that reveals Americans continue to get more than 50 percent of their calories from low-quality carbohydrates and artery-clogging saturated fat.
In their analysis of the eating habits of nearly 44,000 adults over 16 years, NIH-funded researchers attributed much of our nation’s poor dietary showing to its ongoing love affair with heavily processed fast foods and snacks. But there were a few bright spots. The analysis also found that, compared to just a few decades ago, Americans are eating more foods with less added sugar, as well as more whole grains (e.g., brown rice, quinoa, rolled oats), plant proteins (e.g., nuts, beans), and sources of healthy fats (e.g., olive oil).
Over the last 20-plus years, research has generated new ideas about eating a proper diet. In the United States, the revised thinking led to the 2015-2020 Dietary Guidelines for Americans. They recommend eating more fruits, vegetables, whole grains, and other nutrient-dense foods, while limiting foods containing added sugars, saturated fats, and salt.
In the report published in JAMA, a team of researchers wanted to see how Americans are doing at following the new guidelines. The team was led by Shilpa Bhupathiraju, Harvard T. H. Chan School of Public Health, Boston, and Fang Fang Zhang, Tufts University, Boston.
To get the answer, the researchers looked to the National Health and Nutrition Examination Survey (NHANES). The survey includes a nationally representative sample of U.S. adults, age 20 or older, who had answered questions about their food and beverage intake over a 24-hour period at least once during nine annual survey cycles between 1999-2000 and 2015-2016.
The researchers assessed the overall quality of the American diet using the Healthy Eating Index-2015 (HEI-2015), which measures adherence to the 2015-2020 Dietary Guidelines. The HEI-2015 scores range from 0 to 100, with the latter number being a perfect, A-plus score. The analysis showed the American diet barely inching up over the last two decades from a final score of 55.7 to 57.7.
That, of course, is still far from a passing grade. Some of the common mistakes identified:
• Refined grains, starchy vegetables, and added sugars still account for 42 percent of the average American’s daily calories.
• Whole grains and fruits provide just 9 percent of daily calories.
• Saturated fat consumption remains above 10 percent of daily calories, as many Americans continue to eat more red and processed meat.
Looking on the bright side, the data do indicate more Americans are starting to lean toward the right choices. They are getting slightly more of their calories from healthier whole grains and a little less from added sugar. Americans are also now looking a little more to whole grains, nuts, and beans as a protein source. It’s important to note, though, these small gains weren’t seen in lower income groups or older adults.
The bottom line is most Americans still have an awfully long way to go to shape up their diets. The question is: how to get there? There are plenty of good choices that can help to turn things around, from reading food labels and limiting calories or portion sizes to exercising and finding healthy recipes that suit your palate.
Meanwhile, nutrition research is poised for a renaissance. Tremendous progress is being made in studying the microbial communities, or microbiomes, helping to digest our foods. The same is true for studies of energy metabolism, genetic variation influencing our dietary preferences, and the effects of aging.
This is an optimum time to enhance the science and evidence base for human nutrition. That may result in some updating of the scoring system for the nation’s dietary report card. But it will be up to all of us to figure out how to ace it.
References:
[1] Trends in Dietary Carbohydrate, Protein, and Fat Intake and Diet Quality Among US Adults, 1999-2016. Shan Z, Rehm CD, Rogers G, Ruan M, Wang DD, Hu FB, Mozaffarian D, Zhang FF, Bhupathiraju SN. JAMA. 2019 Sep 24;322(12):1178-1187.
Links:
Eat Right (National Heart, Lung, and Blood Institute/NIH)
Dietary Fats (MedlinePlus, National Library of Medicine/NIH)
ChooseMyPlate (U.S. Department of Agriculture)
Healthy Eating Index (Department of Agriculture)
NIH Nutrition Research Task Force (National Institute of Diabetes and Digestive and Kidney Disease/NIH)
Dietary Guidelines for Americans (U.S. Department of Health and Human Services)
Shilpa Bhupathiraju (Harvard T. H. Chan School of Public Health, Boston)
Fang Fang Zhang (Tufts University, Boston)
NIH Support: National Institute on Minority Health and Health Disparities; National Institute of Diabetes and Digestive and Kidney Diseases
Snapshots of Life: Tales from the (Intestinal) Crypt!
Posted on by Dr. Francis Collins
Caption: This “spooky” video ends with a scientific image of intestinal crypts (blue and green) plus organoids made from cultured crypt stem cells (pink).
As Halloween approaches, some of you might be thinking about cueing up the old TV series “Tales from the Crypt” and diving into its Vault of Horror for a few hours. But today I’d like to share the story of a quite different and not nearly so scary kind of crypt: the crypts of Lieberkühn, more commonly called intestinal crypts.
This confocal micrograph depicts a row of such crypts (marked in blue and green) lining a mouse colon. In mice, as well as in humans, the intestines contain millions of crypts, each of which has about a half-dozen stem cells at its base that are capable of regenerating the various types of tissues that make up these tiny glands. What makes my tale of the crypt particularly interesting are the oval structures (pink), which are organoids that have been engineered from cultured crypt stem cells and then transplanted into a mouse model. If you look at the organoids closely, you’ll see Paneth cells (aqua blue), which are immune cells that support the stem cells and protect the intestines from bacterial invasion.
A winner in the 2016 “Image Awards” at the Koch Institute Public Galleries, Massachusetts Institute of Technology (MIT), Cambridge, this image was snapped by Jatin Roper, a physician-scientist in the lab of Omer Yilmaz, with the help of his MIT collaborator Tuomas Tammela. Roper and his colleagues have been making crypt organoids for a few years by placing the stem cells in a special 3D chamber, where they are bathed with the right protein growth factors at the right time to spur them to differentiate into the various types of cells found in a crypt.
Once the organoids are developmentally complete, Roper can inject them into mice and watch them take up residence. Then he can begin planning experiments.
For example, Roper’s group is now considering using the organoids to examine how high-fat and low-calorie diets affect intestinal function in mice. Another possibility is to use similar organoids to monitor the effect of aging on the colon or to test which of a wide array of targeted therapies might work best for a particular individual with colon cancer.
Links:
Video: Gut Reaction (Jatin Roper)
Jatin Roper (Tufts Medical Center, Boston)
Omer Yilmaz (Massachusetts Institute of Technology, Cambridge)
The Koch Institute Galleries (MIT)
NIH Support: National Cancer Institute; National Institute on Aging
