In the 80s my parents bought an ioniser for my brother’s room because we had read that negative ions discouraged the release of serotonin in the brain and could also help to reduce asthma. This was before the Internet so we couldn’t spend five minutes researching the claim before buying one. It was a scientific claim in a national newspaper so we assumed it was supported by some evidence. Serotonin is a neurotransmitter in the brain that is associated with feelings of drowsiness – it all seemed plausible! I should point out that electronic, plug-in ionisers do produce lots of negative ions so that part of the claim at least is true. I am not sure the same can be said for the following.
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Himalayan salt is quite fashionable at the moment. It is sodium chloride with traces of other elements (hence the colour) and is dug up in the Punjab (Pakistan) about 300 km from the Himalayas (but who’s counting?) It’s rock salt! This video comes from the Power of Positivity website. I don’t recommend you visit as it is a mass of confusing articles and hundreds of adverts – it is sometimes difficult to distinguish one from the other.
“The amazing energy emitted from a salt rock lamp cannot be dismissed.”
“You have to feel it to believe it.”
The video makes ten core claims for salt lamps.
Improves mood and helps with anxiety.
As Wikipedia might say – citation needed. The claim that negative ions have a positive effect on mood has been researched. It is possible to combine all the available research into a single study by combining the statistics. This is called a meta-analysis. In 2013 a paper of this type was published which concluded, “No consistent influence of positive or negative air ionization on anxiety, mood, relaxation, sleep, and personal comfort measures was observed.”
Neutralises electromagnetic radiation.
What does this mean? Visible light is a form of electromagnetic radiation. Does lighting one of these candles make it dark? Does it interfere with radio reception, take out Wi-Fi signals or stop x-ray machines from working. What a ridiculous, meaningless statement.
Reduces allergy and asthma symptoms.
Given how much distress allergies and asthma causes I hope that this claim is supported by some very good evidence. If not it is a wicked thing to claim. Spoiler Alert! A comprehensive review of 23 research experiments into this claim concluded, “the literature does not clearly support a beneficial role in exposure to negative air ions and respiratory function or asthmatic symptom alleviation. [..] the human experimental studies do not indicate a significant detrimental effect of exposure to positive air ions on respiratory measures. Exposure to negative or positive air ions does not appear to play an appreciable role in respiratory function.”
Increases energy levels.
Another meaningless claim. This is the sort of vague statement that sounds helpful but doesn’t really tell you anything. Is it encouraging the mitochondria to boost their cellular output? Perhaps it allows the body to more effectively use existing ATP. Maybe it is just claiming a psychological effect. Who knows?
Reduces stress and prevents depression.
In the meta-analysis I quoted above it did find that at very high levels of exposure to negative ions there did seem to be a reduction in the symptoms of depression. The problem is that there is no plausible hypothesis for why this might be. The authors suggest that further research would be needed to show a genuine link as it is quite possible that their finding is an anomaly. It is not always enough merely to see an effect. There has to be some prior plausibility for a strong link to be established.
Purifies bacteria from the air.
Negative ions can kill bacteria, that is why curing meat in salt is so effective. Positive ions can also kill bacteria. Deionised water (water with no ions) kills bacteria as well. You can read more about it here. One significant problem is that, unlike my brother’s electronic ioniser, these lamps almost certainly do not produce significant levels of negative ions. There is no reason to suppose that heating up salt releases negative ions into the atmosphere.
Relieves migraine headaches.
Migraines are very unpleasant headaches. Nobody really knows what causes them so I doubt that a salt lamp casting a dim glow can do much for them. People with migraines often have increased sensitivity to bright light so the soft glow of a salt lamp might be more pleasant than the harsh light of a normal light bulb.
Increases focus and concentration.
If negative ions reduce levels of serotonin in the brain then it might help you to feel less drowsy. (I would remind you though that these lamps are probably not producing a significant concentration of negative ions.) Confusingly Wikipedia says serotonin “is popularly thought to be a contributor to feelings of well-being and happiness.” This would be the de-stressing effect mentioned before which rather works at odds with the increased focus and reduced drowsiness. It is almost as if this stuff is all made up.
Creates a Feng Shui vibe.
Spoiler Alert! Feng Shui, the ancient Chinese art of enhancing mystical energy (Chi and Sha) through harmonising the environment with nature, has absolutely no evidence to support it. When tested Feng Shui practitioners give conflicting advice and no properly blinded study has shown that a genuine effect exists.
Allows for better sleep.
Maybe a night light does allow people to sleep better – the soft glow is very pleasing. An article on the Power of Positivity website claims that sleeping in total darkness is better for your health so who knows what to believe?
I especially enjoyed the comment at the end of the video.
“Any size lamp can help, but the bigger the lamp, the stronger the healing power.”
Essentially saying that you can buy a cheap lamp and that’s fine, but if you want to see some real results get an expensive one! It is possible that these people do not know that they are selling a product that cannot possibly fulfil a fraction of their claims. Conditions like depression, asthma and migraines have really serious effects on people’s lives and science has yet to provide complete solutions for them. If these people do know that they are selling impossible hopes for serious problems then they are beneath contempt as human beings. But that is just my opinion.
Questions…
- Suggest two reactants you could combine to produce the compound sodium chloride.
- How can you help to ensure large crystals when evaporating saturated salt solution?
- What steps would you take to produce a pure dry sample of sodium chloride from some rock salt?
- In what unit is energy measured?
- Salt crystals emit “amazing energy” according to the video. What does a scientist mean when they use the word energy?
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