Do sugary foods cause dementia people to get aggressive or violent?

My Mother was having memory problems for years now....Mom always loved her sweets and if you bought her ice cream she could eat the whole carton in one day.
Mom has been diagnosed with dementia and has white mass matter images in her brain.
We started to realize that when Dad would buy her sweets the next day she was even more confused and forgetful and tired. This would last for a couple days and then it would happen again. Dad liked to treat Mom with treats of sweets.
One time he mentioned to me how bad she was and Dad said he woke up in the morning and she was eating the ice cream out of the carton. And later that day she was very agitated and confused. It was then we realized it was the sugar in the ice cream. So then we decided no sweets for Mom.
Dad then bought ice cream Byers that says No sugar. And then we started to see the same behavior. Dad said it is not the ice cream because it says no sugar. I had him look at the ingredients. No sugar was added but there was still 5 grams of sugar in 1/4 cup. I said Mom eats like half the carton in one day. He did not believe me but every time she ate the ice cream same thing happened. Finally Dad believed me since he is the one who has to live with her and deal with her.
When I took Mom to the Dr she said oh no she is not diabetic so sugar would not have that effect on her. My advice everyone is different and Yes sugar effects my Mother in a bad way. I notice the difference when I talk to her and then I would ask Dad what did she eat today and sure enough it was something with sugar in it....He would say it was only a half of a donut. Well donuts have a lot of sugar in them. Sugar is evil on the brain and the body and is in so much of what we eat.
Mom was put on Aricept and we ended up taking her off of it because it caused her more side effects than being helpful for her brain. It made her compulsive and it made her scratch herself to the point where she would bleed. Since she has been off of it she is less active and she is forgetful. But when she eats right and sleeps good she is much better is is not as bad.
Dad is the caregiver at 91 yrs old and I wish he could get more help with Mom. If people would realize that just talking with her and sitting with her helps her feel good and not so lonely and that is good for the brain.
One more thing to mentioned. A few times Mom was very aggressive and at one point it was so bad she was seeing bugs coming out of the mirrors. Dad had to remove the mirrors in the house and before that he hung up towels over them and she said they still are getting out and coming at her. It was so frightful to hear the fear in her voice and all Dad could do was say there are not bugs. In her mind there were. The Dr was going to put her on drugs for it and then I mentioned I read she could have a UTI? So the Dr said okay lets test her and sure enough she did have a UTI. It took a while for the bug fiasco to go away. Dad took out the mirror in her room and will not put it back up. Anytime she has been overly agitated and aggressive she had tested positive for a UTI. We give her cranberry capsules and since then she has not had a UTI since. Thank GOD.
I hope that anyone reading this finds this helpful. It has been a long year and a half and I live long distance from my Mother and Father. I talk to Mom 3 - 4 x a day and have gotten to know her moods and what helps and what doesn't. She will be 87 in July and has good days and not so good days. It is sad when I hear her say she looks forward to dying because she is lonely. Advice to anyone reading this. Go visit. You cannot make them do anything but you can sit with them and make them laugh and laughter is the best medicine for anyone along with conversation.
God bless ALL you caregivers . It is not easy and It is stressful and you all need support and answers and understanding.

You might want to read this account of sugar's reaction on one person:

https://medium.com/writers-guild/the-horrifying-effect-of-sugar-on-dementia-72753c8e041d

You might also want to read this article, even though it's an older one:

https://www.theguardian.com/lifeandstyle/2017/apr/20/stroke-and-dementia-risk-linked-to-low-sugar-drinks-study-finds

Some months ago I did research on contributing factors, including sugar, and decided to cut out sugar, and chocolate, as I suspected it was also affecting and delaying healing of a back injury I had sustained.    I could see the change in a few days, and although I relapse occasionally,  my consumption will never return to pre-injury levels.  

I can also tell the effect when I relapse and have a cookie.  

It makes sense to me, w/o finding supporting research, that sugar's affect on the human brain accelerates its activity, and with dementia in the picture, it could be  heightened.

No. In fact, the taste of sweets is the last taste sensation to go. Mom was never aggressive or violent. Mom suffered extremely bad stages of Alzheimer's--she eventually became practically brain dead in the end. In the end I had to put in a feeding tube because I did not want her to die of dehydration which is extremely slow and agonizing (despite what hospice says, it is NOT a humane way to die): It often takes about two weeks to die without fluids. I used the feeding tube as a last resort, and she never bothered with it and I never had a problem with it.

Ice cream with protein shakes were my best friend BEFORE mom had to have a feeding tube put in because that's all she ate. I gave her a multivitamin in the form of gummy bear, one a day. She ate that. Her labs were real good for a long time. If that's all she ate that's better than nothing! Despite this, and her insulin-dependent diabetes (IDDM), I kept her sugars under control. She managed to live to 90 years, 3 months--this includes her IDDM, 10 years of chronic kidney disease, and liver problems...all associated with her diabetes. You DO need to keep her teeth clean. The mouth bacteria can be a major source of pneumonia. That was very difficult in the end but I managed. Oral care is just as important even with a feeding tube.

Alzheimer's disease did NOT kill mom. Her years and years and years and years of being diabetic did. Mom also died with perfect skin, and I kept her on a bowel schedule every tuesdays, thursdays and Sundays like clockwork. Thanks to lactulose. Her needs were met, nutrition needs met, kept clean she never had to have any narcotics or psychotropics and she died very peacefully -- she was on hospice for two solid years. She felt loved and secure in her home and I took care of her every single moment.

At great cost--I sacrificed my life for her. She died when I was 59 years old...and caring for her all those years will impact me for the rest of my life not in a good way. At 59 I had to start over. That's very late in life and I no longer have my mom and left alone in the world. I'm still recovering from her loss.

I wrote my thesis on diet and dementia. Many longitudinal studies have been done on the diet and preventing ]=, slowing, and even reversing dementia but for some reason, this information remains widely unknown.
Food does affect your brain, whether your brain is ill or not.
Foods that cause inflammation - sugar, dairy, processed foods, Gluten - are not good for any brain
Non inflammatory foods, - MCT oil, berries, greens, oily fish, etc are good for any brain

My dad is recovering slowwwwly from brain surgery last year and has Delerium still. He has many of the same symptoms as dementia but they are less and less as time goes on.
In the afternoon he gets restless and as he is walking and stronger again it is troublesome. I make him a milkshake with nut milk, banana berries, walnuts and MCT oil powder. within 20 mins he is calm and happy and relaxing on the couch.
It may not work for yours, but please try it... nothing to lose!!!
At the very least , 1 tablespoon of MCT oil a day, can really help (it is like pure brain food)

Not much information found about how sugar might affect those who already have dementia, but it is indicated as one of many things that can contribute in some way to dementia. The only articles about sugar and aggression focus on ADHD, bipolar and the like, but it is a possibility it might affect some. Not every dementia patient has the same symptoms and behaviors - they share a lot, but each person is unique.

That said, do beware. It isn't just added sugar or candies/sweets. So many packaged food items today contain sugar, foods that don't even need sugar. Why? It's a cheap filler and it's also addictive. If possible, eliminate processed foods (boxed, canned, bottled) and make your own. The more natural the state of the food item, the better. Then if sugar is required in the recipe, YOU can control how much to use and when. Funny story - when my daughter was in middle school, she gave a chocolate chip cookie to the bus driver. The driver caught up with me and said she HAD to have my recipe! I told her to use the one on the back of the chocolate chip bag, but cut BOTH sugars in half. That was it!

Read ingredient labels of food items you buy - not just that white label they slapped on more recently, the ingredients. I was appalled years ago to see sugar in PB. The PB we ate as kids are what is now sold as "natural" PB. There's NO need for sugar in PB (should be peanuts and maybe some salt) or many other foods it is in now. Even worse, for those trying to cut calories to lose weight, beware those "fat-free" or "low-fat" items. In removing the fats, the taste is lost, so they add SUGAR! Might as well just slather it on your hips. My research and goal was to avoid cholesterol meds and though it took a while (the "experts" have become enlightened since then), one of the items to avoid was hydrogenated oil, partially or fully. This is used to extend "shelf life" of products. Avoid that if you can! That's also when I started reading ingredients. Even "healthy" items like granola bars are BAD.

I make my own pasta sauce, no sugar needed. Most of the foods I buy are plain frozen or fresh fruits and veggies, nothing added, and meat, though I don't eat a lot of that. I eliminated soda long ago, and the one time I had one later, it nearly gagged me. Any recipe that does call for sugar, I cut the amount down, usually half of what's listed. Oh, on the topic of soda - another item to ditch, esp diet sodas. If I need fizz, I drink sparkling water (carbonated) but always check ingredients for sugar or artificial sweetener and any other nasty ingredients. Read this:

https://www.medicalnewstoday.com/articles/310909

Also, when reading the ingredients, know that they also try to "hide" the added sugar by calling it by other names. Check this site for some more info:

https://www.hopkinsmedicine.org/health/wellness-and-prevention/finding-the-hidden-sugar-in-the-foods-you-eat

For the most part, food items naturally contain sugar, in varying amounts. This isn't the biggest concern, it is the added REFINED and modified sugars that likely cause the most problems. The body has to work to break down natural sugars in the food we eat. Refined sugar is already broken down, so again, slather it on your hips rather than ingesting it! Take the time to prepare your foods from scratch to eliminate these hidden dangers.

For OP or anyone else who might observe this change in behavior, about the best you can do is try trial and error (almost forgot - with any abrupt sudden change in behavior/demeanor, check for UTI or other infection.) Cut down sugary and hidden sugar items and monitor behavior for a few weeks. If no instances, perhaps try it one day and if it happens again, you'd have your answer.

Also look up the sugar in milk. It might surprise you.
My DH is diabetic. He will drink a glass of milk thinking he is having a “healthy” snack then wonder why his blood sugar reading jumps up.
Great you made the connection.

Sugar did effect my mom and tended to make her agitated and more aggressive. I found that even peanut butter would cause behavior issues. Sometimes she would want a candy bar, I would give in with a mini Halloween size treat, then she would want more and more. She was a sugar junkie as long as I could remember. I think that her consumption of sugar also was a factor in developing Alzheimer's.

Drastic mood changes are all too common in dementia which unfortunately worsens over time. It happened to my dad over a period of several years. I'm sorry you're going through this. I don't think sugary foods are the cause at all.

My husband gave my mom, with Alzheimer's, a small dish of banana pudding, maybe just 2 teaspoonfuls, for a snack. Within an hour, she was bouncing off the walls. Eventually, she calmed down. We never gave her anything sugar-laden after that, and no other food seemed to have that effect on her, so we're assuming there was some connection, (although I couldn't say that for sure). I imagine everyone's body can react differently to food. I even wrote a book about taking care of her called, "My Mother Has Alzheimer's and My Dog has Tapeworms: A Caregiver's Tale." I tried to write it with humor and heart, since you need both when dealing with Alzheimer's.

My dad was 90, had AZ and cancer. He liked to eat most foods & loved anything sugary. Our hospice nurse told me Alzheimers was similar to diabetes of the brain. She recommended we limit his sugar intake after noon saying it might help him sleep better & not get as anxious & agitated later. We did that & Dad felt good about having his sweet treat, but was less revved up in the evenings. He still sundowned at times, but honestly, not as often. We would not be militant about his diet b/c as someone else mentioned, there become fewer & fewer simple pleasures our LO’s can enjoy, but it did seem to improve his demeanor & behavior to some extent w/o some kind of pill or medicine. Good luck- wishing you & your family only the best!!