The ZRT Laboratory Blog

The ZRT Blog is an extensive resource for patients and health care providers searching for health and hormone testing information. Here, you can read about ZRT’s cutting edge research, advances in testing, wellness advice, and health industry highlights.



Dr. Alison McAllister

Alison McAllister, ND is the Clinical Consultant Manager at ZRT Laboratory.
Find me on:


Recent Posts

Keeping Your Child Safe From Toxic Baby Food

Posted by Dr. Alison McAllister on Friday, 10 November

baby-food-contamination-313271-edited.jpg

Is there anything more endearing than the photographs of your baby eating his or her first foods? Their faces squish-up, they are covered from head to toe, their tongues protrude to catch every bite or more often to try to get the revolting taste out of their mouths.

Now, we parents are the ones squishing up our faces and showing huge grimaces of disgust at the latest report that our baby food is contaminated by metals – arsenic, lead, cadmium – none of it monitored or regulated by the FDA.

The non-profit Clean Label Project independently analyzed 500 baby formulas and prepared baby foods (formula, food, pouches, snacks, drinks, cereals) from 60 companies and found the following horrifying information. 

Read More

Cortisol Patterns For Graveyard (Shift) Workers

Posted by Dr. Alison McAllister on Tuesday, 31 October

ThinkstockPhotos-152158830.jpg

If you come by ZRT on Halloween you’re likely to be greeted by a witch, vampire, zombie or other nightcrawler. We take our decorations and dressing up seriously around here, and finding people in costume processing your labs or taking your calls is par for the course.

Laughing aside (and let me tell you, some costumes are hilarious) those who live their lives by night – on the graveyard shift – can really struggle.

Two primary challenges for people who work at night are energy and fatigue. This is largely due to the pineal gland and its interaction with light that triggers and enforces our body’s pre-programmed circadian rhythm – which produces high cortisol in the morning and then drops throughout the day until the lowest value at night. For those who work graveyard shift that normal circadian rhythm must be re-established, and for many people it doesn’t happen.

Read More

Pheochromocytoma - A Rare Condition Exposed by Neurotransmitter Testing

Posted by Dr. Alison McAllister on Wednesday, 28 June

ThinkstockPhotos-678500614-lores.jpg

The New York Times did a remarkable story the other day that ended with the line "When you hear hoofbeats, the chances are good that it's a horse…but we must also remember that sometimes the circus is in town. [1]

ZRT is apparently hosting the circus this year. At the odds of 3-8 individuals per million – ZRT has been instrumental in discovering two cases of pheochromocytoma tumors in the last six months. A condition that my clinical physiology teacher, Dr. Bettenburg, said was so rare that we would never see one, and if we did, we should contact her – so I did, this week. 

Read More

A Year of Saliva Testing in Research

Posted by Dr. Alison McAllister on Friday, 23 December

ThinkstockPhotos-AA049539.jpg

I wanted to share a few of the studies using saliva testing that were published in the literature in 2016.

Just a hint, if you want to search for articles on saliva testing, use pubmed.gov and search saliva estradiol (or progesterone, testosterone etc.).

Be aware that saliva hormone testing is so standard in the research world that rarely is it mentioned in the titles of the papers. Over 310 studies were published in 2016 using saliva testing – 61 studies for testosterone and 189 studies on cortisol, while poor progesterone was neglected with only 14 studies this last year.

It’s always good to know that the work that ZRT has been doing for almost 20 years in the field of saliva testing is still cutting edge and useful. 

Read More