Sweet Potatoes

Farmers grow sweet potatoes for food and feed markets. Pet food makers use the harvested roots fresh or dry and grind them into flour. This ingredient is a crop, not a processing leftover.^4,7

1. 01 // Source Harvested roots Growers harvest the starchy storage roots, whose flesh varies from white to orange or purple by variety.
2. 02 // Process Cleaned and cut Roots intended for drying are cleaned, then shredded or sliced before moisture is removed.
3. 03 // Process Dried and ground For flour, cut roots are dried and ground; fresh roots skip this step.
4. 04 // Output Roots or flour Fresh roots or dried flour reach the pet food plant, where extrusion cooks the starch in kibble.

1. 01

   Usable energy from cooked starch

   Starch is nearly three quarters of dried root weight, and cooking lifts the easily digested starch share from 4% to 55%, which is why extruded kibble turns it into usable calories.^6,7

   1. Strong
   2. Some
   3. Thin
   4. None
2. 02

   A gentler blood sugar rise after meals

   In 2 small dog trials, sweet potato diets gave smaller glucose rises than corn, potato, pea or cereal diets. One sweet potato food also held less starch, and neither trial included diabetic dogs.^1,11

   1. Strong
   2. Some
   3. Thin
   4. None
3. 03

   More fermentation in the colon

   Dogs fed a sweet potato diet had higher stool short chain fatty acids and more Faecalibacterium, signs of colon fermentation. The tradeoff is real: that diet had the lowest digestibility of 7 tested.^4,11

   1. Strong
   2. Some
   3. Thin
   4. None
4. 04

   Beta carotene from orange varieties

   Orange roots carry beta carotene, and Beagles absorbed purified doses of 50 to 100 mg a day. No study has measured how much a sweet potato food delivers, or any health effect from it.^2,7

   1. Strong
   2. Some
   3. Thin
   4. None

1. 01

   Supplies starch energy

   Starch makes up most of the root's dry weight. Cooking increases the share available to digestive enzymes, so sweet potatoes fill a carbohydrate role in the recipe.^6,7

2. 02

   Helps form kibble

   Starch changes during extrusion and helps the kibble expand. A dog food study made kibble with sweet potato flour, though the processor had to adjust the added water.⁴

3. 03

   Replaces grain starch

   Flour gives manufacturers a starch source for recipes without grain. Roots are grown widely, but turning a crop that is mostly water into dry flour adds processing.^5,7

4. 04

   Adds a recognizable vegetable

   Orange varieties contain beta carotene, giving manufacturers a familiar ingredient to discuss. The name on a bag does not disclose the flesh color or carotene amount.⁷

How much One 24-dog study tested sweet potato flour at 17.77%, 35.56% and 53.33% of the formulas by weight.⁴

1. Brands say

   Sweet potatoes give dogs useful energy

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   Dried-root samples averaged 72.8% starch on a dry matter basis, and cooking makes more sweet potato starch accessible to digestive enzymes. It is an energy ingredient; the complete food determines how much energy a dog gets.^6,7

2. Brands say

   Sweet potatoes keep blood sugar steady

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   In a 15-dog crossover trial, the sweet potato diet produced the smallest glucose and insulin responses, but it also held less starch than the comparison diets. A flour study reported a smaller maximum rise above baseline than rice. Neither tested diabetes control.^1,4

3. Brands say

   Sweet potato fiber improves gut health

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   In a 24-dog study, more sweet potato flour increased fecal fermentation products, but digestibility and stool dry matter fell. Those measurements show a gut effect; the study did not demonstrate better health.⁴

4. Brands say

   Beta carotene improves dogs' eyesight

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   Orange sweet potatoes contain beta carotene. Dogs absorbed purified beta carotene in feeding experiments lasting up to 30 days, but those experiments fed no sweet potatoes and measured no vision outcomes. The variety on a bag is unknown.^2,7

5. Owners say

   Sweet potatoes cause heart disease in dogs

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   An analysis of 18 diets could not evaluate sweet potatoes: they appeared in too few foods in either comparison group. FDA says the broader diet and heart disease question involves multiple factors. This evidence does not identify sweet potatoes as a cause.^3,8

1. 2023 // Feeding trial, 3 commercial foods

   Sweet potato food produced the smallest blood sugar rise¹

   15 healthy neutered adult dogs

   Found. Total blood sugar over 6 hours after a meal was about 6% lower with the sweet potato food than the cereal food (34,236 vs 36,406 mg/dL·min), and insulin was lowest too. Farmina, a pet food maker, partly funded it.

   What it means. A modest gap in healthy dogs. The sweet potato food also held less starch, 25% vs 28%, so the root alone cannot take the credit.

2. 2000 // Feeding experiments, purified doses

   Dogs absorb beta carotene into blood and immune cells²

   Mature Beagle dogs

   Found. Single doses up to 200 mg raised blood beta carotene, peaking at 6 hours with a half-life of 3 to 4 hours. Daily doses of 50 or 100 mg for 30 days raised it in white blood cells.

   What it means. Dogs can take up beta carotene, but these were purified doses, not sweet potato, and no eye or immune outcome was measured.