A Research Topic

Research topics are generated from problems in your field of study; (unknown, unclear and unsolved issues that are of great relevance) ; and not a research topic coming out of the blue.
Often people ask for Research Topics to investigate but then this question seems too blunt.
On the other hand, if we can brainstorm on problems facing the Food Science and Human Nutrition Field, we can generate research topics to solve these problems.
I’ll start it off:

The number of Cancer Patients in my country, Uganda is increasing gradually, what foods(functional) can help solve this dilemma; What products can I develop from these foods?

Great topic and functional drink market is growing everywhere.
Any fruit including mangosteein, berry (various types), passion fruit, or those available regionally would be great for such application. Natural fruits and vegetables / extracts / powders are high in demand and they are being added to normal drinks to increase functionality of the product.
We could even look at the food waste such as the peels of pumpkin, grapefruit, banana and others, while seeds are another group of materials that can be powdered well for incorporation - improve the total phenolic content or even antioxidant potential of the drink. While chia seeds, amaranth seeds are all gaining popularity in drinks. I believe Lots of research within the flavor and ingredient industry is going on in this area.

" The number of cancer cases is increasing gradually In Uganda", is something that must be addressed first and start asking.: WHY…?..

I would agree with @Roy. Identifying the cause of this would be more impactful than addressing the symptoms. And you might possible address other concerns along the way, not just cancer.