In UK the larger super market chains have online websites:
www.tesco.com
www.asda.com
www.sainsburys
and they sell multivitamins too.
For example, to find information about Tesco's vitamins:
1. enter tesco.com
2. select groceries (if not already selected)
3. specify search key multivitamins
PRESS Enter
You get a long list of matching multivitamins (some also containing minerals). The match 'Tesco A-Z Multivitamins & Minerals 90S' shows:
Tesco Multivitamins and Minerals
Nutrition
Typical Values One tablet %RI*
Vitamin D 10.00µg 200
Vitamin K 75.0µg 100
Thiamin (Vitamin B1) 1.10mg 100
Riboflavin (Vitamin B2) 1.40mg 100
Pantothenic acid 6.0mg 100
Vitamin B6 1.40mg 100
Folic Acid 200µg 100
Vitamin B12 2.50µg 100
Biotin 50.0µg 100
Vitamin C 80mg 100
Calcium 200mg 25
Magnesium 100.0mg 27
Iron 14.0mg 100
Copper 1.00mg 100
Iodine 150.0µg 100
Zinc 10.0mg 100
Manganese 2.0mg 100
Selenium 55.0µg 100
Chromium 40µg 100
Molybdenum 50.0µg 100
* Recommended Daily Amount - -
and you can then compare with multi vitamins available in Cambodia.
You can also find nutrients of all foods sold on these UK supermarket websites. Spinach is good for keto-diets. Search for it on the Tesco website and you will get the macro nutrients:
Typical Values Per 100g spinach
Energy 115kJ/28kcal
Fat 0.8g
Saturates 0.1g
Carbohydrate 0.5g
Sugars 0.3g
Fibre 3.0g
Protein 3.1g
Salt <0.01g
but vitamin and mineral content is normally not shown.
For a full nutrition description of spinach you can go to US Department of Agriculture's (USDA's) FoodData Central website:
https://fdc.nal.usda.gov/
and enter search key 'spinach'.
You will get a long list of matches. Ignore those marked 'Branded' and select 'Spinach, raw, SR Legacy...' which shows a list of nutrients per 100g of spinach. In this list you will see Magnesium 79mg, Potassium 558mg and Sodium 79mg.
I think you can probably get all nutrients the body needs from eating local foods in Cambodia. The USDA FoodData Central may help to eliminate foods that are too high in carbohydrates for keto-diets.