We asked you for your (health-related) view of ice baths, and got the above-depicted, below-described, set of responses:

• About 31% said “ice baths are great for the health; we should take them”
• About 29% said “ice baths’ risks outweigh their few benefits”
• About 26% said “ice baths’ benefits outweigh their few risks”
• About 14% said “ice baths are dangerous and can kill you; best avoided”

So what does the science say?

Freezing water is very dangerous: True or False?

True! Water close to freezing point is indeed very dangerous, and can most certainly kill you.

Fun fact, though: many such people are still saveable with timely medical intervention, in part because the same hypothermia that is killing them also slows down the process* of death

Source (and science) for both parts of that:

Cold water immersion: sudden death and prolonged survival

*and biologically speaking, death is a process, not an event, by the way. But we don’t have room for that today!

^{(unless you die in some sudden violent way, such as a powerful explosion that destroys your brain instantly; then it’s an event)}

Ice baths are thus also very dangerous: True or False?

False! Assuming that they are undertaken responsibly and you have no chronic diseases that make it more dangerous for you.

What does “undertaken responsibly” mean?

Firstly, the temperature should not be near freezing. It should be 10–15℃, which for Americans is 50–59℉.

You can get a bath thermometer to check this, by the way. Here’s an example product on Amazon.

Secondly, your ice bath should last no more than 10–15 minutes. This is not a place to go to sleep.

What chronic diseases would make it dangerous?

Do check with your doctor if you have any doubts, as no list we make can be exhaustive and we don’t know your personal medical history, but the main culprits are:

• Cardiovascular disease
• Hypertension
• Diabetes (any type)

The first two are for heart attack risk; the latter is because diabetes can affect core temperature regulation.

Ice baths are good for the heart: True or False?

True or False depending on how they’re done, and your health before starting.

For most people, undertaking ice baths responsibly, repeated ice bath use causes the cardiovascular system to adapt to better maintain homeostasis when subjected to thermal shock (i.e. sudden rapid changes in temperature).

For example: Respiratory and cardiovascular responses to cold stress following repeated cold water immersion

And because that was a small study, here’s a big research review with a lot of data; just scroll to where it has the heading“Specific thermoregulative adaptations to regular exposure to cold air and/or cold water exposure“ for many examples and much discussion:

Health effects of voluntary exposure to cold water: a continuing subject of debate

Ice baths are good against inflammation: True or False?

True! Here’s one example:

Winter-swimming as a building-up body resistance factor inducing adaptive changes in the oxidant/antioxidant status

Uric acid and glutathione levels (important markers of chronic inflammation) are also significantly affected:

Uric acid and glutathione levels during short-term whole body cold exposure

Want to know more?

That’s all we have room for today, but check out our previous “Expert Insights” main feature looking at Wim Hof’s work in cryotherapy:

A Cold Shower A Day Keeps The Doctor Away?

Enjoy!

Is Dairy Scary?

Milk and milk products are popularly enjoyed as a good source of calcium and vitamin D.

In contrast, critics of dairy products (for medical reasons, rather than ethical, which is another matter entirely and beyond the scope of this article) point to risks of cancer, heart disease, and—counterintuitively—osteoporosis. We’ll focus more on the former, but touch on the latter two before closing.

Dairy & Cancer

Evidence is highly conflicting. There are so many studies with so many different results. This is partially explicable by noting that not only is cancer a many-headed beast that comes in more than a hundred different forms and all or any of them may be affected one way or another by a given dietary element, but also… Not all milk is created equal, either!

Joanna Lampe, of the Public Health Sciences division, Fred Hutchinson Cancer Research Center in Seattle, writes:

❝Dairy products are a complex group of foods and composition varies by region, which makes evaluation of their association with disease risk difficult. For most cancers, associations between cancer risk and intake of milk and dairy products have been examined only in a small number of cohort studies, and data are inconsistent or lacking❞

In her systematic review of studies, she noted, for example, that:

• Milk and dairy products contain micronutrients and several bioactive constituents that may influence cancer risk and progression
• There’s probable association between milk intake and lower risk of colorectal cancer
• There’s a probable association between diets high in calcium and increased risk of prostate cancer
• Some studies show an inverse association between intake of cultured dairy products and bladder cancer (i.e., if you eat yogurt you’re less likely to get bladder cancer)

Since that systemic review was undertaken, more research has been conducted, and the results are… Not conclusive, but converging towards a conclusion:

• Dairy products can increase or decrease cancer risk
• The increase in cancer risk seems strongest when milk is consumed in quantities that result in too much calcium. When it comes to calcium, you can absolutely have too much of a good thing—just ask your arteries!
• The decrease in cancer seems to be mostly, if not exclusively, from fermented dairy products. This usually means yogurts. The benefit here is not from the milk itself, but rather from the gut-friendly bacteria.

You may be wondering: “Hardened arteries, gut microbiome health? I thought we were talking about cancer?” and yes we are. No part of your health is an island unrelated to other parts of your health. One thing can lead to another. Sometimes we know how and why, sometimes we don’t, but it’s best to not ignore the data.

The bottom line on dairy products and cancer is:

• Consuming dairy products in general is probably fine
• Yogurt, specifically, is probably beneficial

Dairy and Heart Disease

The reason for the concern is clear enough: it’s largely assumed to be a matter of saturated fat intake.

The best combination of “large” and “recent” that we found was a three-cohort longitudinal study in 2019, which pretty much confirms what was found in smaller or less recent studies:

• There is some evidence to suggest that consumption of dairy can increase all-cause mortality in general, and death from (cancer and) cardiovascular disease in particular
• The evidence is not, however, overwhelming. It is marginal.

Dairy and Osteoporosis

Does dairy cause osteoporosis? Research here tends to fall into one of two categories when it comes to conclusions, so we’ll give an example of each:

1. “Results are conflicting, saying yes/no/maybe, and basically we just don’t know”
2. “Results are conflicting, but look: cross-sectional and case-control studies say yes; cohort studies say maybe or no; we prefer the cohort studies”

See them for yourself:

1. Osteoporosis: Is milk a kindness or a curse?
2. Consumption of milk and dairy products and risk of osteoporosis and hip fracture

Conclusion: really, the jury is very much still out on this one

Summary:

• Moderate consumption of dairy products is almost certainly fine
• More specifically: it probably has some (small) pros and some (small) cons
• Yogurt is almost certainly healthier than other dairy products, and is almost universally considered a healthy food (assuming not being full of added sugar etc, of course)
• If you’re going to have non-dairy alternatives to milk, choose wisely!

That’s all we have time for today, but perhaps in a future edition we’ll do a run-down of the pros and cons of various dairy alternatives!