An important new study this week published in Nature by Brody Foy and colleaguesshed new light on the importance of personalized reference values—intra-individual variation— and the enormity of data and insights that can be gleaned from this way to analyze one’s CBC data. In this edition of Ground Truths, I’m going to review the main results and the implications for how this advances the field of individualized (a.k.a. precision) medicine
It’s about body weight, but how is it determined in blood biomarkers? I mean how to calculate my set point for specific biomarkers in my CBC panel? Is it an arithmetic mean of a parameter during a certain time period?
From Grok 2:
Calculating your personal set point, typically related to body weight, involves understanding a few key concepts:
Basal Metabolic Rate (BMR):
This is the number of calories your body needs to maintain basic functions while at rest. You can estimate it using formulas like the Harris-Benedict Equation:
For men: BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) - (5.677 × age in years)
For women: BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) - (4.330 × age in years)
Activity Level:
Multiply your BMR by an activity factor:
Sedentary (little or no exercise): BMR × 1.2
Lightly active (light exercise/sports 1-3 days/week): BMR × 1.375
Moderately active (moderate exercise/sports 3-5 days/week): BMR × 1.55
Very active (hard exercise/sports 6-7 days a week): BMR × 1.725
Extra active (very hard exercise/sports & physical job or 2x training): BMR × 1.9
Genetics and Set Point Theory:
The set point theory suggests that your body has a weight range it tries to maintain. While genetics play a role, lifestyle factors like diet, exercise, and sleep can influence this range.
Caloric Intake vs. Expenditure:
If you consistently consume more calories than you burn, your body might adjust its set point upwards. Conversely, a significant caloric deficit can lower it, but this is often temporary without lifestyle changes.
Practical Steps:
Track Intake: Use apps or diaries to log food intake to see if it matches your calculated caloric needs.
Monitor Changes: Gradually adjust calorie intake and observe how your weight responds without drastic changes.
Lifestyle: Incorporate sustainable changes in diet, exercise, and sleep, which can influence your set point more effectively than temporary diets.
Remember, the concept of a “set point” isn’t exact science; it’s more about understanding how your body tends to react to changes in weight. If you’re looking to adjust your weight, consider professional advice from nutritionists or doctors who can tailor advice to your specifics.
A “set point” appears to be a point for a particular function that your body decides works “best”. Probably the “easiest” point for a particular data set to maintain homeostasis. This set point does not seem to have the requirement for ideal health or function.
The weight thing, is a good example. All the factors that combine to establish “your” set point for a stable weight come into play, genetics, diet, activity, metabolism, etc are factors that establish the set point for a stable weight. Not always an ideal weight but a point that is easiest to maintain under the long term established life style and genetics.
And set points can be changed. Now that “fat memory” is becoming more fully understood and how that is an epigenetic process that can be changed is one of the more interesting aspects of set points.
Hopefully somebody can post this paper which is really interesting because those tests are very common and we have
For instance here is the relationship for 9 different CBC values by quintile for 10-year mortality.
This shows which ones have linear or U shape hazard ratio and if it’s a positive or negative one.
For instance MCV, RDW and WBC have a strong negative linear association. The higher they are the worse it is.
On the other hand MCHC have a strongly positive linear association: The higher it is the better.
The other ones are less strongly correlated but still interesting anyway.
Then they looked at how things improve or deteriorate when your values change from what they used to be (your setpoints) to a new value.
For instance for RDW, if it was high and it’s now low then it’s all good (blue). On the other hand if it was low and is now high then it’s pretty bad (dark red)
Looks like I do need to improve my MCHC from low to high!
When you are talking “low” or “high”, do you mean low or high within normal range or outside the normal range? I also may need to improve my MCHC as it is very close to the bottom of the normal range (32.1). The question is how to make it higher?
In that paper low or high refers to the values they define on the plots at the bottom of the second figure.
For instance for MCHC low is 33.3 and high would be 33.7.