Parents across the UK face a familiar dilemma this Halloween: how to let children enjoy the fun of trick-or-treating without overloading on sugar. Health agencies and dentists warn that a single night of unchecked snacking can trigger more than tummy aches. Heavy sugar intake strains teeth and metabolism. Black liquorice carries a specific heart risk when people eat large amounts. Sherbet and sour treats bathe teeth in acid as well as sugar. Authorities do not call for bans or alarm; they urge moderation, label checks and a plan for the treat bowl. As households stock up, the guidance feels timely and practical: know what is in the sweets, keep portions small, and protect teeth.
Context and timing
Halloween falls on 31 October, when trick-or-treating peaks in towns and villages across the UK. Seasonal reminders from health bodies typically arrive in the final week of October. This year is no different, with dentists, paediatricians and food regulators repeating clear, long-standing advice on sugar limits, black liquorice risks and dental care.
How much sugar is too much? What NHS and WHO say
The NHS advises adults not to exceed 30g of free sugars per day. It sets lower limits for children: 19g a day for ages 4 to 6, and 24g for ages 7 to 10. Free sugars include those added to foods and drinks, plus sugars in honey, syrups and fruit juices. The World Health Organization recommends that both adults and children keep free sugars below 10% of daily energy intake, with a further reduction to below 5% offering additional benefits. These limits help reduce risks of tooth decay and unhealthy weight gain.
On Halloween, many children collect a week’s worth of sweets in a single evening. Large hauls do not have to mean large intakes. Experts recommend that families set simple rules: choose a few favourites on the night, put the rest away, and spread treats over several days. Eating sweets at mealtimes, rather than constantly snacking, reduces the time teeth sit in sugar and acid. Water and milk help clear sugars from the mouth. Sugary drinks increase the load; health agencies advise against them, especially for young children.
Black liquorice: why glycyrrhizin can raise blood pressure and disturb heart rhythm
Black liquorice contains glycyrrhizin, a compound from liquorice root. Glycyrrhizin affects how the body handles cortisol, which in turn makes the kidneys retain sodium and lose potassium. That shift can raise blood pressure and, in high doses, trigger irregular heart rhythms. The risk rises in older adults and people with heart disease, kidney disease or high blood pressure. Some medicines also increase risk, including certain diuretics and drugs that affect heart rhythm.
The United States Food and Drug Administration has warned for several years that eating about 57g (two ounces) of black liquorice a day for at least two weeks could lead to an abnormal heart rhythm in adults over 40. Doctors reported a fatal case in 2020 after a man ate large amounts of black liquorice daily for several weeks. While such events remain rare, they show why “natural” does not always mean harmless. UK shoppers sometimes meet liquorice in mixed sweets, herbal teas and flavoured products. People who take medicines for blood pressure, heart disease or kidney issues should read labels and speak to a pharmacist if unsure.
Sherbet and sour candies: acid plus sugar is a double hit for teeth
In the UK, sherbet usually refers to a fizzy powder that combines sugar with acids such as citric or tartaric acid and sodium bicarbonate. It differs from American “sherbet,” which is a frozen dessert. Many sour candies use similar acids to deliver a sharp taste. Dentists highlight two problems: high sugar feeds bacteria that cause decay, and acidity softens enamel. Tooth enamel begins to dissolve at a pH of around 5.5. Some sour sweets and sherbets can drop saliva pH to near 2 or 3 during and after eating.
You can protect teeth with simple steps. Offer sherbet and sour treats with meals, not between them. Encourage children to rinse with water or drink milk after acidic snacks. Wait at least 30 minutes before brushing, so softened enamel can reharden. Sugar-free chewing gum, particularly gum with xylitol, can increase saliva and help neutralise acids; it suits older children who can chew safely. Always keep xylitol products away from dogs, as xylitol is toxic to pets even in small amounts.
Children’s health: short-term spikes and long-term patterns
A Halloween sugar blowout can cause brief energy surges and crashes, along with stomach aches in some children. For most healthy children, a single night does not cause lasting harm. The longer-term pattern matters more. Diets high in free sugars link to tooth decay, excess weight and higher risk of type 2 diabetes. In England, tooth decay remains a leading cause of hospital admissions for children aged 5 to 9. Dentists see sticky sweets, lollipops and frequent snacking as common culprits because they keep sugar in contact with teeth.
Parents can look for labels that show “free sugars” or check the ingredients list for added sugars like glucose syrup, fructose and sucrose. Chocolate often clears from the mouth faster than chewy toffees or sticky gummies. Dark chocolate usually contains less sugar than milk chocolate, but
