Dad’s having a dip, some sort of decline, which I hope is temporary.

It may be because we’ve had a change in carer, something which didn’t bother Mum when she was being looked after, because she didn’t have dementia. But for Dad the change of face, of voice, accent, touch and smell brings with it a feeling of uncertainly and he retreats into himself.

I have also been out and about more than usual – Carolyn’s back in town, so we’ve been on some jaunts – and Dad has started asking me how long I’m going out for and when I’ll be back. I feel like a teenager again – the only difference is I’m (mostly) back home well before my erstwhile curfew!

The skin on Dad’s face has become very red and angry looking. This may be due to an overabundance of cake – compensation for all the changes - and that can cause a flare up. We’re now having more plain biscuits (Rich Tea and ‘squashed fly’ Garibaldis), along with more fruit. And Dad’s skin does seem to be settling down.

The gurus at Alzheimer’s Scotland have given me some leaflets about dementia and diet, not just to help Dad but also to help myself because often the seeds of dementia may be sown 30– 40 years before the symptoms show.

As a lifelong vegetarian I have always been interested in food, not just as fuel but as a source of health and pleasure. I have embraced blueberries and cherry juice (full of anti-oxidants) and tried to warn my friends and inert siblings of the dangers of aspartame (Google it along with ‘Alzheimer’s’ ). I’ve urged Dad’s carers to give him more fresh fish and less basic value microwave meals, but I’ve usually been met with scepticism or downright disdain.

The advice from Alzheimer’s Scotland is mostly the stuff we’ve all heard before – eat more fruit and vegetables, eat more fish. Eat more starchy foods  - bread, cereals, rice, pasta and potatoes - the wholegrain, wholemeal or brown varieties where possible.

But get this – one American study found a 60% reduction in the risk of Alzheimer’s disease in people who ate oily fish at least once a week.

Another study found that people who drank fruit or vegetable juice more than three times a week had a 76% lower risk of developing Alzheimer’s disease than those who drank juice less than once a week.

This isn’t airy-fairy alternative diet stuff, this is science. Real evidence. And it's easy.

The list of things that are contraindicated is pretty obvious too – stop smoking, don’t drink too much alcohol, cut down on salt, reduce fat and sugar.

There isn’t much in the way of specific research on sugar and dementia but too much sugar can affect Dad in much the same way as some children – there’s a short period of hyperactivity, followed by a complete collapse. Like a puppet whose strings have been cut, Dad crumples and barely has the strength to lift his head. He becomes more muddled and harder to understand and it takes another meal and plenty of fluids to get him back to normal.

Dehydration exacerbates the symptoms of dementia and sugar somehow causes dehydration, so what starts as a treat can end up as a lethal cocktail.

Dad’s CPN (Community Psychiatric Nurse) first alerted me to this a couple of years ago, during one of her routine visits to the house. She rang me in London and ranted about how Dad was surrounded by toffee wrappers and seemed to be living on a diet of Coca Cola and cake, with crisps in between times. She was horrified, but the previous regime had promised her that this was a one-off, that Dad never normally had cake and that the fizzy drink was just a ‘wee treat’. I knew this to be nonsense but I had no way of managing what Dad was eating from 400 miles away. That, coupled with the ‘if you can’t eat cake when you’re 90 when can you?’ campaign, left me feeling completely powerless.

Now that I’m back at home I can see how easily Dad’s mood, his digestion, his ability to concentrate and his skin are all affected by what he eats and drinks.

So I’m trying very hard to give him a little of what he fancies, alongside plenty of the good foods and as much fluid as I can get into him. Since I’ve been back (over six months now) I haven’t given him Coca Cola once – and the really odd thing is, he has never asked for it.

I am off to Rome – I’ve reinstated the trip I had to postpone when Dad was rushed into hospital before Christmas. So I’ll be enjoying a diet of home-made pasta, wafer thin pizza, fresh vegetables and tomatoes that actually taste like tomatoes! And of course there will also be room for my favourite Italian gelato, and lashings of local wine. Can’t wait!

While I’m away some important things are happening – it’s Alex’s birthday and, on the same day, my pal Clare. Altogether now, to the Altered Images tune: ‘Happy Birthday, Happy Birthday….’

My next posting will be in two weeks.