Fifteen Health Beliefs That Are Not True
Some health beliefs are harmless. Others delay treatment or cause direct injury. Here is a set of common ones with what the evidence actually shows.
“Curd at night causes a cold”
No. Colds are caused by viruses. Curd does not change mucus production or susceptibility. Milk can thicken the sensation of mucus in the mouth temporarily, which is probably where the belief comes from, but it does not increase mucus volume or cause infection. Curd at night is fine, and it is a useful source of protein and calcium.
“Cracking knuckles causes arthritis”
No. The sound is a gas bubble collapsing in the joint fluid. Studies, including one researcher who cracked the knuckles of one hand for over 60 years and not the other, found no difference in arthritis. It may slightly reduce grip strength with very heavy habitual cracking, but it does not cause arthritis.
“You must drink eight glasses of water a day”
Not a real rule. Requirements vary with body size, climate, activity and diet, and a substantial proportion of intake comes from food. Thirst and pale urine are better guides than a fixed count. Over-drinking is possible and in extreme cases causes dangerously low sodium.
“Sugar makes children hyperactive”
Repeatedly tested and not supported. Double-blind studies in which parents were told their child had received sugar rated the child as more hyperactive regardless of what was actually given. The expectation is doing the work. Sugar has plenty of real harms; this is not one of them.
“Eating fat makes you fat, and fat causes heart disease”
Oversimplified to the point of being wrong. Total calories matter for weight. For heart disease, the type of fat matters: unsaturated fats are protective, trans fats are clearly harmful, and saturated fat has a more complex relationship than the older blanket advice implied. Refined carbohydrate and sugar were under-blamed for decades.
“Detox diets and cleanses remove toxins”
They do not. The liver and kidneys do this continuously, and no juice, tea, foot patch or colon cleanse improves their function. The named “toxins” are almost never specified. Prolonged juice cleanses cause muscle loss and electrolyte problems, and colon cleansing can perforate the bowel.
“Vaccines cause autism”
No. The single 1998 paper claiming a link was found to be fraudulent and retracted, and its author was struck off the medical register. Studies involving millions of children across many countries have found no association. The diseases prevented are real and dangerous.
“Antibiotics cure colds and flu”
No. Those are viral and antibiotics have no effect on viruses. Taking them gives you all the side effects, no benefit, and contributes to resistance that may harm you later when you genuinely need them.
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“Toothpaste on a burn helps”
It does the opposite. It traps heat, introduces infection, and must be scrubbed off later, which is painful and damaging. The correct treatment is cool running water for 20 minutes. The same goes for ice, butter, ghee and ink.
“Put a spoon in the mouth during a seizure”
Dangerous. It breaks teeth, injures the jaw and risks choking. A person cannot swallow their tongue. Protect the head, time the seizure, turn them on their side when it stops, and put nothing in the mouth.
“Sunlight is enough to treat newborn jaundice”
No, and this belief causes real harm. Sunlight cannot deliver a controlled therapeutic dose, risks burning, dehydration and hypothermia, and above all creates false reassurance while bilirubin keeps rising. Phototherapy in hospital is the treatment, and severe untreated jaundice causes permanent brain damage.
“Cold weather causes colds”
Not directly. Viruses cause colds. Cold seasons increase transmission because people gather indoors, ventilation falls, and some viruses survive better in cold dry air. Nasal temperature may also slightly reduce local immune response. Getting wet in the rain does not by itself give you an infection.
“Papaya leaf extract treats dengue”
Evidence is weak and the practice is harmful when it substitutes for monitoring. In dengue, what determines outcome is fluid management and watching for warning signs of plasma leakage, not the platelet count alone and certainly not a leaf extract. Treating at home with remedies while warning signs develop is how dengue deaths happen.
“You lose most of your body heat through your head”
A misreading of an old military study in which subjects were dressed except for their heads. Heat is lost roughly in proportion to exposed surface area. Hats are useful; the specific claim is not.
“Reading in dim light damages your eyes” and “sitting close to the TV ruins vision”
Neither causes permanent damage. Dim light causes eye strain and fatigue, not harm. Children who sit very close to a screen are often doing so because they are short-sighted, not the other way round, which is a reason to test their vision.
Beliefs that happen to be true
Not everything handed down is wrong:
- Turmeric has genuine anti-inflammatory compounds, though absorption from food is poor and the evidence for medicinal doses is still thin
- Ginger has reasonable evidence for nausea
- Honey suppresses cough in children over one year, better than many cough syrups. Never give honey under one year, because of infant botulism risk
- Steam inhalation eases nasal congestion symptomatically
- Saline nasal irrigation genuinely helps rhinitis and sinusitis
- Oil massage for babies improves weight gain and sleep in preterm infants
- Hand washing with soap is one of the most effective public health measures ever devised
- Walking after meals measurably lowers post-meal blood glucose
How to judge a health claim
Ask who benefits from you believing it. Ask whether there is a plausible mechanism. Be suspicious of anything that claims to cure many unrelated conditions, of testimonials in place of trials, of “doctors don’t want you to know”, and of any remedy sold with urgency. And treat the absence of harm as a weak defence when the alternative is delayed real treatment.
This is general information. Where a belief concerns treating an actual illness, follow medical advice rather than tradition, and ask your doctor rather than an internet list.