Thyroid hormones

• As part of my work, I rely on various health-related biomarkers, many of which are measured using conventional blood tests.
• Understanding what common blood tests are intended to measure can help you better interpret the results.
• If you have results from a recent blood test handy, please follow along.

Normal blood test ranges

• This range is essentially the upper and lower limits within which most healthy people’s test results are expected to fall.
• To determine how your test results compare with the normal range, you need to check the reference interval listed on your lab report.
• If you have results for a given test from different labs, your clinician will likely focus on test trends relative to their reference intervals and not the numerical results themselves.

Interpreting your blood test results

• There are numerous blood panels intended to test specific aspects of your health.
• These include panels that look at the cellular components of your blood, biomarkers of kidney and liver function, and many more.

• This results from either lower than normal levels of red blood cells or a decrease in the quantity or quality of hemoglobin, the protein that allows these cells to transport oxygen.
• A complete blood count panel measures various components of the blood to provide a comprehensive overview of the cells that make it up.
• Low values of red blood cell count, or RBC, hemoglobin, or Hb, and hematocrit, or HCT, would indicate that the patient is suffering from anemia.
• Providing additional information is the basic metabolic panel, or BMP, which measures the amount various substances in your blood.

With results from each of these panels, the health professional would assess the patient’s values relative to their reference intervals and determine which condition they most likely have. Understanding the purpose of blood tests and how to interpret them can help patients partner with their health care providers and become more informed about their health.
Brad Reisfeld does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

• LONDON, July 13, 2023 /PRNewswire/ -- A research team from The London Psychiatry Centre (TLPC) has discovered new genetic biomarkers in bipolar spectrum disorder .
• This discovery may pave the way for the first ever diagnostic lab test in psychiatry.
• It reported a surprising number of mutations occurring in bipolar spectrum disorder compared to the general population.
• We may well be 24-36 months away from a diagnostic lab test for bipolar spectrum disorder.

• These chemicals are found in food packaging, waterproof cosmetics, non-stick pans, stain- and water-resistant fabrics and carpeting, cleaning products, paints and fire-fighting foams.
• As environmental health researchers, we believe that the government needs to regulate and, eventually, stop the continued release of persistent toxic PFAS into the environment and also prevent the creation of any toxic replacements.

How do PFAS affect us?

• The widespread use of these chemicals can be attributed to the strong chemical bond between the carbon and fluorine atoms that make up the backbone of PFAS.
• However, that strong bond also leads to PFAS taking years, even decades, to break down in the environment.
• For example, larger, older fish tend to contain higher concentrations of PFAS compared to smaller, younger fish.
• A Canadian study found that at least 65 per cent of infants were exposed to PFAS in the womb.

Regulating PFAS

• Canada also regulates another subset of PFAS called long-chain perfluorocarboxylic acids.
• However, there are over 4,700 PFAS, and the Canadian and international regulations in place only cover a tiny fraction of the forever chemicals in the market.

Populations at highest risk

• As public health scientists try to catch up with the industry’s unrestrained chemical production, some populations are put at heightened risk of PFAS exposure, including firefighters, pregnant women and Arctic Indigenous populations.
• As emphasized in our report, Inuit living in Nunavik have some of the highest PFAS concentrations worldwide.
• Some compounds measured in their blood were up to seven times higher than the concentrations measured in the rest of the Canadian population.

Towards better regulation

• Yet, we know little about the impact of being exposed to multiple PFAS at a time.
• Ongoing scientific studies are trying to understand the implications of mixtures on our health and how to regulate these forever chemicals accordingly.
• The Canadian report is a necessary step to inform future regulations and stop the continued release of persistent PFAS in the environment.

• Maybe you’re fatigued and can’t concentrate, then wake up in the middle of the night.
• The latest TikTok wellness trend would have you believe high cortisol levels are to blame.
• But so do thyroid hormones, appetite hormones and sex hormones, as well as diet and physical activity.

Why is cortisol portrayed as bad?

• Some of what is being blamed on cortisol are symptoms of chronic stress or depression – which makes sense, since these are linked.
• This might make people think cortisol is bad for them, but this is not the case.

Cortisol is essential for a healthy stress response

• In a healthy and normal stress response, cortisol rises quickly in response to the stress and then rapidly reduces back to baseline levels after the stress has passed.
• Chronic stress can cause dysregulated cortisol secretion: when cortisol remains high even in the absence of an immediate stress.
• It can take weeks for cortisol dysregulation to return to normal after chronic stress.

What’s the link with depression?

• Our research team has shown that people with depression have, on average, higher cortisol than people who don’t have depression.
• The symptoms described on TikTok as being due to high cortisol may be caused by stress, depression or anxiety.
• Low cortisol can be caused by chronic stress and high cortisol during childhood or earlier in life.
• This is why some people with depression, particularly those with a long history of depression, have low rather than high cortisol.

How do you know if your cortisol is too high or low?

Despite claims on TikTok, we cannot tell whether our cortisol is in balance or high or low. The only way to know is to have your blood, urine or saliva analysed in a laboratory. This is not done routinely and would be a waste of resources. A doctor would only check this if they suspected you had a disorder of cortisol production, but these are rare. Besides, your cortisol levels vary considerably across different times of the day and night.

Cortisol affects your body clock

• One of the most important roles of cortisol is in the circadian system of the body.
• Cortisol communicates these signals from the brain to the rest of the body.

How can you maintain healthy cortisol levels?

• You can try to maintain healthy levels of cortisol by addressing the underlying causes of cortisol dysregulation.
• Exercise during the day and good sleeping habits also help to reduce chronic stress and high cortisol.