Monthly Archives: January 2020

High-Fiber Diets Are Associated With Reduced All-Cause Mortality Risk

A meta-analysis of 10 studies, including 80,139 subjects was recently published that shows a significantly reduced risk of death for all causes in association with higher total dietary fiber intakes (35-39g/day), when compared with lower fiber (Reynolds et al. 2019):

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Should we supplement with fiber, or get it from whole food? Fiber from whole foods was significantly associated with lower levels of fasting glucose, body weight, whole body fat mass, LDL cholesterol, and triglycerides. Supplementation with fiber extracts or bran was not significantly associated with the reduction of any of these variables (NS, not significant; NM, not measured:




Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. 2019 Feb 2;393(10170):434-445. doi: 10.1016/S0140-6736(18)31809-9.


If you’re interested, please have a look a my book!


An Interview With Dr. Michael Lustgarten: Biohacker, Scientist

  • How (and why) did you get involved in research in aging and the human microbiome?
  • How did you get started in health optimization /  quantified-self?
  • What are your thoughts on biological age testing? Which tests (epigenetic, blood biomarkers, telomere, etc) and specific services do you believe to be most useful?
  • What else is in your biohacking stack? (Nutrition / diet, fasting, wearables or other products, fitness routines, supplements, drugs, services, lifestyle practices, sleep, mental)

And much more!

Green Tea and Mortality Risk, Update!

In an earlier post (, I reported that green tea consumption is associated with reduced risk of death for all causes. Now, there’s more recent data! Drinking more than 1 cup of green tea per day is associated with reduced all-cause mortality risk in a pooled analysis of 8 studies that included 313,381 subjects (age range, 40-103y; Abe et al. 2019).

In women (168,631 subjects), risk of death for all causes was reduced by 10%, 6%, and 18% for 1-2, 3-4, and greater than 5 cups/day, when compared with drinking less than 1 cup per day:

gt wom

In men (144,750 subjects), risk of death for all causes was reduced by 5%, 7%, and 10% for 1-2, 3-4, and greater than 5 cups/day, when compared with drinking less than 1 cup per day:

gtea men.png

Cheers to green tea, for health!


Abe SK, Saito E, Sawada N, Tsugane S, Ito H, Lin Y, Tamakoshi A, Sado J, Kitamura Y, Sugawara Y, Tsuji I, Nagata C, Sadakane A, Shimazu T, Mizoue T, Matsuo K, Naito M, Tanaka K, Inoue M; Research Group for the Development and Evaluation of Cancer Prevention Strategies in Japan. Green tea consumption and mortality in Japanese men and women: a pooled analysis of eight population-based cohort studies in Japan. Eur J Epidemiol. 2019 Oct;34(10):917-926. doi: 10.1007/s10654-019-00545-y.

If you’re interested, please have a look at my book!

Uric acid: What’s optimal?

The reference range for uric acid is 4.0 – 8 mg/dL for men, and 2.5 – 7 mg/dL for women. Are these values optimal for health? To answer that question, let’s have a look at how circulating levels of uric acid change during aging, and their association with risk of death for all causes.

Uric acid increases during aging in both men and women. Kuzuya et al. (2002) studied how uric acid changes during a 10-year intervals for various birth cohorts, including 32yr olds, 39yr olds, 47yr olds, 56yr olds, and 65 yr olds (1960-1969, 1950-1959, 1940-1949, 1930-1939, 1920-1929 birth cohorts, respectively). For each birth cohort, uric acid levels increased during aging for men (left image below), whereas they increased for women starting at 40 years old:

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In terms of mortality risk, lowest risk of death for all causes was associated with uric acid levels of 5 – 7 mg/dL for men and 4 – 6 mg/dL for women in the 9,118 adults (average age, 43y) of Hu et al. (2019). Also note the U-shaped curve for both genders, whereas mortality risk increases at both low and high levels of uric acid:

Screen Shot 2020-01-05 at 2.55.00 PM.png

Similarly, the lowest risk of death for all causes was associated with uric acid levels of 7 mg/dL for men, and 4 mg/dL for women in the 375,163 adults (average age, 40y) of Cho et al. (2018), with mortality risk significantly increasing at uric levels < 3.5 and > 9.5 mg/dL for men, < 2.5 and > 7.5 mg/dL for women. Collectively, these 2 studies in middle-aged adults suggest that uric acid levels ~ 4 mg/dL for women and ~7 for men may be optimal for reducing risk of disease for all causes. It’s also important to note that both low and higher values are associated with an increased mortality risk.

The data for the Hu and Chu studies are in younger adults, so how does the data look in older adults? Lowest all-cause mortality risk was associated with uric acid levels between 4 – 5 mg/dL in the 121, 771 older adults (average age, 73y) of Tseng et al. (2018), with mortality risk significantly increasing below 4 and > 8:

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What are my uric acid levels? From 2016 to 2018, I measured it 15x, and although my average value of 5.2 mg/dL is not too low or too high in terms of an increased all-cause mortality risk, it increased during that 3-year period (R2 = 0.2886). When considering that uric acid increases during aging, can I reduce it with diet?

ua ml

Because I track my daily nutritional intake, I can look for correlations between my dietary intake with circulating biomarkers. Interestingly, a moderately strong correlation between my lycopene intake with uric acid (R2 = 0.3343, p=0.024) was present from 2016 to 2018:

ua vs lyco.png

Lycopene is found almost exclusively in tomatoes and watermelon. If these foods are related to my increasing levels of uric acid, if I ate less of them, I’d expect to see a corresponding decrease in uric acid. So, in 2019, I ate less of these foods, thereby reducing my average lycopene intake from 11,585 to 9,132 micrograms per day. How did that affect circulating levels of uric acid?

In 6 measurements for 2019, my average uric acid level was 4.6 mg/dL, a value that was significantly different (p=0.02) from the 2016-2018 average of 5.2 mg/dL. Whether eating less watermelon and tomatoes caused the decrease is unknown, but it’s good to know that uric acid can be potentially modified with dietary change!

my ua


If you’re interested, please have a look at my book!


Cho SK, Chang Y, Kim I, Ryu S. U-Shaped Association Between Serum Uric Acid Level and Risk of Mortality: A Cohort Study. Arthritis Rheumatol. 2018 Jul;70(7):1122-1132. doi: 10.1002/art.40472.

Hu L, Hu G, Xu BP, Zhu L, Zhou W, Wang T, Bao H, Cheng X. U-Shaped Association of Serum Uric Acid with All-cause and Cause-Specific Mortality in US Adults: A Cohort Study. J Clin Endocrinol Metab. 2019 Oct 25. pii: dgz068. doi: 10.1210/clinem/dgz068.

Kuzuya M, Ando F, Iguchi A, Shimokata H. Effect of aging on serum uric acid levelslongitudinal changes in a large Japanese population group. J Gerontol A Biol Sci Med Sci. 2002 Oct;57(10):M660-4.

Tseng WC, Chen YT, Ou SM, Shih CJ, Tarng DC; Taiwan Geriatric Kidney Disease (TGKD) Research Group. U-Shaped Association Between Serum Uric Acid Levels With Cardiovascular and All-Cause Mortality in the Elderly: The Role of Malnourishment. J Am Heart Assoc. 2018 Feb 10;7(4). pii: e007523. doi: 10.1161/JAHA.117.007523.

Resting Heart Rate, Heart Rate Variability: December 2019 Update

In earlier posts, I reported year-over-year improvements for my resting heart rate (RHR), from 51.5 (bpm) when I first started tracking in August 2018 to 48 bpm in November 2019 ( Did my year-over-year RHR improvement continue in December 2019?

As shown below, in December 2018, my average RHR was 49.5 bpm. In December 2019, it was 47.5! These data are significantly different (p=6.5E-05):

rhr dec 2019

While RHR is one metric of cardiovascular health, heart rate variability (HRV) is another. With a stronger heart, the expectation would be a lower RHR, but a higher HRV. December 2019 was my best month ever for HRV, with an average HRV value of 86.3!

hrv 12 2019

Also note that December 2019’s HRV value is significantly different when compared with December 2018 (p=1.6E-11).

How am I able to continuously improve my RHR, and recently, my HRV? I average 15-20 miles of walking per week, and 3-4 days/week of structured exercise (1 hr/session), including a combination of weights, core, and stretching. My average HR during my structured workouts had been ~105 bpm prior to the past few months, but in November and December 2019 I made more of an effort to minimize rest periods, and included higher reps to keep my exercise HR as high as possible. My goal is to get my RHR to 40 bpm, which is associated with maximally reduced risk of death for all causes ( Stay tuned for more RHR and HRV data next month!

If you’re interested, please have a look at my book!