Africa Swap Diet Study

Question 1

Colon cancer risk in African Americans

Answer 1

Colorectal cancer disproportionately affects the Black community, and they are more likely to die from it than any other group

Question 2

6 components of the standard American diet

Answer 2

• meat-based
• high-calorie
• high-fat
• high-sodium
• low-fibre
• high in sugar

Question 3

How are meat and colon cancer connected?

Answer 3

Colon cancer is more common among people who eat red and processed meat

Question 4

Red meat

Answer 4

Unprocessed mammalian muscle meat (beef, veal, pork, lamb, horse, and goat)

Question 5

Processed meat

Answer 5

Bacon, ham, sausage, and hot dogs preserved by smoking, curing, salting, or adding chemical preservatives such as nitrates and nitrites

Question 6

What chemicals made in meat processing that is associated with colon cancer?

Answer 6

Carcinogens such as NOC and PAH, heme iron facilitates production of carcinogenic NOCs, and high-temp cooking can produce carcinogenic chemicals (HAA and PAHs)

Question 7

Soluble dietary fibre

Answer 7

Fibre that dissolves in water; creates a thick gel that slows nutrient absorption, prevent blood spikes and insulin levels, traps dietary fat and bile, and helps feed gut good bacteria

Question 8

Insoluble dietary fibre

Answer 8

Fibre that does NOT dissolve in water; increases transit time, adds bulk to stool, prevent constipation/hemorrhoids/diverticulitis, and helps feed gut good bacteria

Question 9

Gut microbiota and western diet

Answer 9

Low gut microbiota diversity is associated with the Western diet

Question 10

How is colon health in rural Africans?

Answer 10

Rural africans eating a traditional diet have lower prevalence of colon cancer, lower colonic epithelial proliferation rates, and fewer premalignant colonic lesions (polyps)

Question 11

4 components of the Traditional African diet

Answer 11

• Minimally processed
• High in fibre and starchy carbohydrates
• Low in animal protein (small portions of meat and few eggs)
• Low dairy intake (often fermented)

Question 12

What was the health of the americans at the start of the swap?

Answer 12

Almost half had polyps, significantly higher mucosal epithelial proliferation, and higher gut inflammation

Question 13

What was the health of the africans at the start of the swap?

Answer 13

No polyps, lower mucosal epithelial proliferation, and lower gut inflammation

Question 14

What foods made up the rural South africans diet?

Answer 14

• stiff maize porridge with salt
• seasonal vegetables
• chicken, goats, and few cattle (scarce and generally used as flavouring)
• Eggs, when available

Question 15

How were the rural south african diet cooked?

Answer 15

Generally boiled, not fried, and cooked in cast iron pots on open wood fires

Question 16

What is the macro composition of the African American diet?

Answer 16

47% carbs, 35% fat, 15% protein (75% animal), and 14g/day fibre

Question 17

What is the macro composition of the Rural South African diet?

Answer 17

72% carbs, 16% fat, 11% protein (34% animal), and 66g/day fibre

Question 18

What are the Canadian daily fibre recommendations?

Answer 18

25g for women, and 38g for men; most are only getting half the recommendations

Question 19

What was the health of the americans at the end of the swap?

Answer 19

Significantly less colon inflammation, and dramatic drop in multiple risk factors for colon cancer (less cell division)

Question 20

What was the health of the africans at the end of the swap?

Answer 20

Cancer risk markers increased dramatically, and there was an increased division of colon cells

Question 21

How did the swap affect the gut microbiome?

Answer 21

African diet increases butyrate production by 250%, a byproduct of fibre metabolism. American diet cut butyrate production in half

Question 22

What health implications (3) are found from the swap study?

Answer 22

1. People can substantially lower risk of colon cancer with more fibre and less red meat
2. Risk markers for colon cancer can rapidly switch
3. Nutrition transition of the African diet coupled with obesity may lead to the emergence of colon cancer as a major health issue in Africa