Optimal Fasting Time Prior to Blood Lipid Testing

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Optimal Fasting Time Prior to Blood Lipid Testing

Postby RussT » Mon May 20, 2019 7:52 am

Hi Jeff,

What is the optimal time one should fast prior to blood lipid testing? Recommendations vary from 8-12 hours and some have reported getting skewed results when fasting over 13 hours. Would fasting longer increase blood lipids?

Can you please share the exact number of hours the patients at TrueNorth fast or your personal observations for the most accurate test results.

Thank you very much!

Russ
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Re: Optimal Fasting Time Prior to Blood Lipid Testing

Postby JeffN » Mon May 20, 2019 11:11 am

RussT wrote: Would fasting longer increase blood lipids? .


Depends on the person and situation. It's possible but it usually takes longer then an extra hour or two before a test.

Isr Med Assoc J. 2000 Mar;2(3):215-9.
Effect of prolonged fasting on plasma lipids, lipoproteins and apolipoprotein B in 12 physicians participating in a hunger strike: an observational study.
https://www.ncbi.nlm.nih.gov/pubmed/10774270

All non-obese normolipidemic males and females (groups 1 and 3) showed an increase in plasma triglyceride (by 28-162%) and very low density lipoprotein cholesterol (by 22-316%) after 3 days of fasting. The obese and hyperlipidemic men (group 2) showed a decrease of 17-63% in their VLDL cholesterol, and the women on oral contraceptives (group 4) showed a 20% decrease in their plasma triglyceride on day 3. Low density lipoprotein cholesterol increased by 13% in group 2, decreased by 7.3% in group 4, and remained unchanged in group 1 and 3. Apolipoprotein B level correlated well with LDL cholesterol in all groups. High density lipoprotein cholesterol changes were inconsistent.

CONCLUSIONS:
These results help to explain and reconcile previous published reports. The metabolic background of the individual together with the amount of energy consumed affect the behavior of plasma lipids and lipoproteins levels during fasting.
[/b]


RussT wrote:Can you please share the exact number of hours the patients at TrueNorth fast or your personal observations for the most accurate test results.


At the 10-Day McDougal Program, we tell patients not to eat after 8:00 PM but to drink water. We draw blood at 7:30 - 8:00 AM, so their fast is about 11-12 hours.

However, since about 2016, they are no longer recommending fasting as being required for lipid panels. Turns out there is not a big difference. Many think the non-fasting lipid panel is better. The exception is if you are monitoring your triglycerides as what you eat (or drink) can impact them fairly quickly and it can last a day or so. Remember, this is just for a lipid panel. We check more then lipids and that is why we require fasting at the program.

My thoughts are for just a lipid panel, pick either one and be consistent.

In Health
Jeff

Here are some articles on it for you.

From Harvard
https://www.health.harvard.edu/blog/far ... 1606169784

From JAMA
https://cyber.sci-hub.se/MTAuMTAwMS9qYW ... ra2016.pdf

The European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine
http://clinchem.aaccjnls.org/content/cl ... 7.full.pdf

European Heart Journal
https://academic.oup.com/eurheartj/arti ... 44/1749006
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Re: Optimal Fasting Time Prior to Blood Lipid Testing

Postby RussT » Mon May 20, 2019 11:56 am

Thank you very much Jeff for the prompt and information filled reply. My lab work has been going in a positive direction for the past three years of following the Dr. McDougall protocols. I have improved my diet and exercise since my last lab work in July 2018 but the numbers went up (see below). I am trying to understand why this occurred but I can't come to any logical conclusions. How in the world can my total cholesterol, Triglycerides, and LDL rise 30 points when I don't eat anything with cholesterol or oils? Note: I fasted for 13 hours, did not eat any fatty foods at all and I did not engage in strenuous exercise prior to the test.

Could this likely be a lab error? Any thoughts you could provide would be greatly appreciated.

MAY 2019
Cholesterol Total (range 125-200 mg/dl) 187
HDL (range >or = 40 mg/dl) 54
Triglycerides (range < 150 mg/dl) 100
LDL (range <100) 112
Chol/HDLC Ratio (range 5.0 or <) 3.5
Non HDL Cholesterol (range < 130) 133

JULY 2018
Cholesterol Total (range 125-200 mg/dl) 157
HDL (range >or = 40 mg/dl) 54
Triglycerides(range < 150 mg/dl) 79
LDL (range <100) 86
Chol/HDLC Ratio (range 5.0 or <) 2.9
Non HDL Cholesterol (range < 130) 103
Last edited by RussT on Mon May 20, 2019 12:02 pm, edited 2 times in total.
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Re: Optimal Fasting Time Prior to Blood Lipid Testing

Postby JeffN » Mon May 20, 2019 12:01 pm

RussT wrote:Thank you very much Jeff for the prompt and information filled reply. My lab work has been going in a positive direction for the past three years of following the Dr. McDougall protocols. I have improved my diet and exercise since my last lab work in July 2018 but the numbers went up (see below). I am trying to understand why this occurred but I can't come to any logical conclusions. How in the world can my total cholesterol rise 30 points when I don't eat anything with cholesterol or oils? Note: I fasted for 13 hours, did not eat any fatty foods at all and I did not engage in strenuous exercise prior to the test.

Any thoughts you could provide would be greatly appreciated.

MAY 2019
Cholesterol Total (range 125-200 mg/dl) 187
HDL (range >or = 40 mg/dl) 54
Triglycerides (range < 150 mg/dl) 100
LDL (range <100) 112
Chol/HDLC Ratio (range 5.0 or <) 3.5
Non HDL Cholesterol (range < 130) 133

JULY 2018
Cholesterol Total (range 125-200 mg/dl) 157
HDL (range >or = 40 mg/dl 54
Triglycerides(range < 150 mg/dl) 79
LDL (range <100) 86
Chol/HDLC Ratio (range 5.0 or <) 2.9
Non HDL Cholesterol (range < 130) 1


There are many variable that can play a role and our lab values are not static numbers but numbers with ranges that depend on these variables. Test your labs 5x a day and you will get 5 different (most likely similar) values. And your trend data would be important to see.

And labs can make errors.

If it was me and I was concerned, I would wait 1-3 months and test again

In Health
Jeff
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Re: Optimal Fasting Time Prior to Blood Lipid Testing

Postby RussT » Mon May 20, 2019 12:06 pm

Once again thank you very much Jeff for your answers. I will get labs done and report back so that others on the board who have a similar experience may benefit.

Have a wonderful day Jeff!

Russ
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Posts: 43
Joined: Tue Feb 26, 2019 10:02 am
Location: Southern California

Re: Optimal Fasting Time Prior to Blood Lipid Testing

Postby JeffN » Wed May 29, 2019 8:30 am

Just to add one more study that just came out

Original Investigation
May 28, 2019
Association of Nonfasting vs Fasting Lipid Levels With Risk of Major Coronary Events in the Anglo-Scandinavian Cardiac Outcomes Trial–Lipid Lowering Arm
JAMA Intern Med. Published online May 28, 2019. doi:10.1001/jamainternmed.2019.0392

https://jamanetwork.com/journals/jamain ... le/2733560

Key Points
Question How do nonfasting lipid levels compare with fasting lipid levels measured in the same individuals for assessing cardiovascular risk, and what is their association with incident cardiovascular events?

Findings In this secondary analysis of 8270 participants in the Anglo-Scandinavian Cardiac Outcomes Trial–Lipid Lowering Arm, nonfasting lipid levels were similar to fasting lipid levels measured 4 weeks apart in the same participants in association with incident cardiovascular events overall and by randomized statin therapy. Concordance of fasting and nonfasting lipid levels for classifying participants into appropriate risk categories was high.

Meaning The present study provides robust evidence supportive of broader adoption of nonfasting lipid level measurement in clinical practice.

Abstract
Importance Recent guidelines have recommended nonfasting for routine testing of lipid levels based on comparisons of nonfasting and fasting populations. However, no previous study has examined the association of cardiovascular outcomes with fasting vs nonfasting lipid levels measured in the same individuals.

Objective To compare the association of nonfasting and fasting lipid levels with prospectively ascertained coronary and vascular outcomes and to evaluate whether a strategy of using nonfasting instead of fasting lipid level measurement would result in misclassification of risk for individuals undergoing evaluation for initiation of statin therapy.

Design, Setting, and Participants This post hoc prospective follow-up of a randomized clinical trial included 8270 of 10 305 participants from the Anglo-Scandinavian Cardiac Outcomes Trial–Lipid Lowering Arm (ASCOT-LLA) with nonfasting and fasting lipid levels measured 4 weeks apart (including 6855 participants with no prior vascular disease) (median follow-up, 3.3 years; interquartile range, 2.8-3.6 years). Data were collected from February 1, 1998, to December 31, 2002, and analyzed from February 1, 2016, to November 30, 2018. Multivariable Cox models, adjusted for cardiovascular risk factors, were calculated for 40-mg/dL (1-mmol/L) higher values of nonfasting and fasting lipids.

Main Outcomes and Measures The trial’s primary end point consisted of major coronary events (nonfatal myocardial infarction [MI] and fatal coronary heart disease [212 events]). Secondary analyses examined atherosclerotic cardiovascular disease (ASCVD) events (including MI, stroke, and ASCVD death [351 events]).

Results Among the 8270 participants (82.1% male; mean [SD] age, 63.4 [8.5] years), nonfasting samples had modestly higher triglyceride levels and similar cholesterol levels compared to fasting samples. Associations of nonfasting lipid levels with coronary events were similar to those for fasting lipid levels. For example, adjusted hazard ratios (HRs) per 40-mg/dL of low-density lipoprotein cholesterol were 1.32 (95% CI, 1.08-1.61; P = .007) for nonfasting levels and 1.28 (95% CI, 1.07-1.55; P = .008) for fasting levels. For the primary prevention group, adjusted HRs were 1.42 (95% CI, 1.13-1.78; P = .003) for nonfasting levels and 1.37 (95% CI, 1.11-1.69; P = .003) for fasting levels. Results were consistent by randomized treatment arm (atorvastatin calcium, 10 mg/d, or placebo) and similar for ASCVD events. Concordance of fasting and nonfasting lipid levels for classifying participants into appropriate ASCVD risk categories was high (94.8%).

Conclusions and Relevance Measurement of nonfasting and fasting lipid levels yields similar results in the same individuals for association with incident coronary and ASCVD events. These results suggest that routine measurement of nonfasting lipid levels may help facilitate ASCVD risk screening and treatment, including consideration of when to initiate statin therapy.
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