Early signs of Alzheimer's as scientists warn of symptom that appear while eating

Scientists have warned that a symptom of dementia can appear while you're eating food. September 21 marks World Alzheimer's Day, which is designed to raise awareness around, educate, encourage support of and demystify dementia.

It is estimated that 850,000 people in the UK are living with the condition, which often causes memory loss and language difficulty and can have a devastating impact on a person's life. There is currently no cure for the condition but diagnosing dementia early enables people to live as well as possible thanks to medicines, treatment and care given by professionals. This means it's important to look out for symptoms of the condition.

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An early sign of Alzheimer's disease, which is the most common form of dementia worldwide, is anosmia (smell loss) or hyposmia (reduced smell) These can present themselves before other symptoms begin and, while symptoms of Alzheimer's disease can be more obvious as time progresses, early detection could be important in slowing the disease down. Research, led by the National Institute of Ageing in the US and published in the Journal of Alzheimer's Disease, found that the decline in sense of smell is connected to the faster build-up of Alzheimer's related pathology seen in brain scans.

The study found that people in their 70s who were unable to identify smells from items such as roses, lemons and onions were significantly likely to develop dementia over the next decade than those who recognised the smells. Willa Brenowitch, the study's lead author and neuroscientist at UCSF, said in a statement: "The olfactory bulb, which is critical for smell, is affected fairly early on in the course of the disease."

"It's thought that smell may be a preclinical indicator of dementia, while hearing and vision may have more of a role in promoting dementia." Alzheimer's disease is a progressive condition, which means the symptoms develop gradually over time and will eventually become more severe. The rate at which symptoms develop for each individual will differ and the first showing symptoms may also vary.

According to the NHS in the early stages, the main symptom of Alzheimer's is memory lapses. Common early symptoms of Alzheimer's disease can include forgetting recent conversations or events, as well as the names of people, places and objects, misplacing items, asking the same questions repeatedly, and finding it harder to make decisions.

People may also have trouble thinking of the right word, become more hesitant to try new things, and get lost in familiar places. The NHS said: "There are often signs of mood changes, such as increasing anxiety or agitation, or periods of confusion."