Q&A: Dr. Kara Fitzgerald on her study showing how to lower biological age
We discussed specific elements of her nutrition, exercise and stress-reducing regimen that lowered the biological ages of her study participants by several years.
This post follows up the article I published last month about a study that showed how a small group of women 46 to 65 lowered their biological ages by an average of almost 5 years by following a strict but achievable daily nutrition, exercise and stress-mitigating regimen.
I subsequently interviewed Dr. Kara Fitzgerald, the lead author of that 2023 study, and asked her about:
The reasons for including liver in participants’ weekly diet (as a whole food or supplement)
Why she kept the daily diet free of beans/legumes and dairy
Her book, “Younger You,” which includes the full daily regimen that her two aging-related studies indicate may consistently lower biological age
The negative impact of stress on biological age
Our conversation also touched on epinutrients, which help turn on processes that benefit our health and lifespans, and briefly on DNA methylation, a biological process that affects how our genes are expressed and, as a result, how we biologically age. More about those in a future post.
But first, liver! Why liver?
Dr. Fitzgerald’s study had participants eating three 3-ounce servings of organic liver a week, either as a whole food or as a supplement, because it packs the biggest punch.
“Liver is the most nutritionally dense food out there,” she told me. “It contains folate, B-12, cholene — those epinutrients that fall in the methyl category.”
If you’re not up for eating liver, she recommends liver supplements, which she said she takes as part of her weekly diet.
The reasons against including beans and dairy in her study
Dr. Fitzgerald avoided including beans in her nutrient plan for study participants, she said, because of it’s propensity to raise blood sugar and cause digestive issues. Dairy is also a “pretty common inflammatory food for a lot of individuals,” she said.
Her 2023 study of middle-aged women was designed, she said, to be broadly tolerable and anti-inflammatory for the study period.
Her book: “Younger You”
Published in 2022, Dr. Fitzgerald’s book includes the specific biological-age-reducing diet in her 2023 study. The book includes a 30-page epinutrient appendix.
The book is a followup to Dr. Fitzgerald's novel 2021 study of 43 healthy men aged 50-72 which, she said, was the first randomized, controlled trial to show biological age reversal through diet and lifestyle changes.
“That 2021 paper was the first of its kind in the world,” she said, and when she formulated the study, in 2019, biological age reversal in humans was not yet an established concept.
Stress reduction as a vital component of lowering biological age
Her 2021 and 2023 studies on how to reduce biological age required participants to do daily breathing exercises that most of those people struggled to complete. The average compliance rate was less than 60%. And yet, according to Dr. Fitzgerald, the exercises, which are meant to reduce the impact of daily stress on one’s aging process, can have a large impact.
“In the literature, it really does seem that stress is a huge factor in aging,” she told me.
A biological age blood test?
Dr. Fitzgerald's website offers a testing package using TruDiagnostic's DunedinPACE of Aging test. (The tests appear to be out of stock as of this writing, fyi.) I haven’t done the test so can’t offer an opinion on it. But the idea is to test your biological age before and after embarking on a daily nutrition, exercise and meditation/breathing regimen for two months or longer.
I’ll write about epinutrients, and their role in biological aging, in a future article.