Amazoniac
Member
Members that find the carotene content of foods so exorbitant that give up and choose to ignore,
In short:
- Carotene is much more difficult to be absorbed from plants in their raw state, they're better absorbed from supplements because they lack the matrix that holds it inaccessible, and cooking in turn makes it more available.
- Just a little dietary fat is enough to allow you to absorb plenty of carotenes, and even in the absence of fat it's possible to absorb if an excess is being ingested, possibly through bile.
- Meals interact, so if you ate plenty of cooked greens on your previous meal for example, and something fatty on the following meal, it's enough to absorb a great deal of the carotenes that remain in the intestines for longer than expected.
- A vitamin A deficiency increases your capacity to absorb carotenes.
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Influence of Dietary Fat on β‐Carotene Absorption and Bioconversion into Vitamin A
"[..]only a limited amount of fat (3 g) is needed for optimal uptake of a- and b-carotene was the conclusion from studies by Roodenburg et al.7 who measured these carotenes in the plasma of 18- to 70- year-old Dutch subjects (n=14) consuming a low-fat (3 g) or a high-fat (36 g) spread enriched with 8 mg of a- plus b-carotene."
"[..]increases in a- and b-carotene were not different in subjects fed low-fat (315% and 139% increase, respectively) or highfat spreads (226% and 108% increase, respectively)."
"Dimitrov et al.8 studied the effects of dietary fat on the bioavailability of b-carotene supplements in healthy U.S. men and women who were 21 to 63 years of age."
"In the group not fed fat together with the b-carotene capsule, smaller plasma b-carotene elevations occurred, with levels being signicantly different from baseline only after 13 to 15 days of treatment; when b-carotene treatment was discontinued, b-carotene levels returned to baseline values 7 to 23 days later."
"In the study by Prince and Frisoli,9 no detectable changes in serum b-carotene were observed in three healthy volunteers (30 –36 years of age) who ingested a single 51-mg dose of b-carotene in the absence of dietary fat."
"As already mentioned, among vitamin A–malnourished children, increases in serum carotenes3 and retinol3,4 were seen when carotene-rich plant foods were ingested even in the absence of fat; these increases were similar to those observed when fat was provided with plant carotenes in the same meal. Among well nourished adults, Dimitrov et al.8 also reported small increases in plasma b-carotene when daily b-carotene supplements were ingested for 3 weeks with a fat-free breakfast followed by a low-fat (6 g fat) midday meal. It is logical to presume that in order for maximal carotene utilization to take place, the fat and carotene sources should be provided in the same meal. When dietary fat is not provided together with b-carotene, however, it is possible that delayed gastric emptying of b-carotene and/or delayed intestinal uptake and release of -carotene into the lymphatic and then blood circulation may occur, provided intraluminal lipids become available from the next meal to allow packaging of b-carotene into chylomicrons. That delayed release of b-carotene from enterocytes can take place is supported by data from human studies.27,28 The timing between the ingestion of -carotene and dietary fat cannot be too far apart, however. Henderson et al.27 reported that in a subject who did not consume food until 16 hours after the b-carotene dose, no increase in serum b-carotene was seen. Perhaps the reverse may also be possible: that some fat from a previous meal may remain in the intestines to aid in the absorption of b-carotene ingested hours later."
"Another possible explanation for b-carotene utilization in the absence of dietary fat is that endogenously secreted fat in the bile may play a role in b-carotene absorption. It is known that bile salts promote vesicular secretion of lecithin and cholesterol into bile, and that the secreted vesicles dissolve into mixed micelles in biles enriched with more hydrophobic bile salts.29 The importance of bile and bile salts in stimulating the absorption of b-carotene from the gastrointestinal tract is well documented.30–32"
"To explain b-carotene absorption in the absence of dietary fat, it has been suggested by Dimitrov et al.8 that the chylomicron–lymphatic system may not be the only pathway for b-carotene transport in humans. Likewise, Borel et al.28 speculated on the possibility of a greater transport of b-carotene via the portal pathway in the presence of medium-chain triglycerides."
"De Pee et al.33 reported that carotenes in orange fruit are more bioavailable than those in green leafy vegetables and carrots because b-carotene molecules in fruit are present in lipid droplets in chromoplasts and can be readily released during digestion. In green leaves, b-carotene molecules are complexed with proteins located in cell chloroplasts and may be more dif cult to release from the matrix; carotenes in carrots exist as crystals, which may not be readily solubilized and absorbed."
It's a matter of amount, though.
"The type of dietary fat may influence the bioavailability of b-carotene from foods and supplements. However, studies with animals have produced conflicting results regarding the effect of different types of fat on b-carotene absorption and metabolism.37–42"
"b-carotene and retinyl palmitate responses in chylomicrons were markedly diminished when b-carotene was provided in a meal with medium-chain triglycerides than when b-carotene was provided with long-chain triglycerides, apparently owing to the lack of secretion of triglyceride-rich chylomicrons in response to dietary medium-chain triglycerides."
"Based on serum retinol or b-carotene responses to meals containing carotenes and different amounts of fat, it has been suggested that only a small amount of fat may be required to ensure carotene utilization in humans — 5 g of fat in a meal containing 40 g of cooked spinach (with ~1.2 mg b-carotene)4[reference] or 3 g of fat for 8 mg of burtlan- plus b-carotene supplements consumed with a meal.7"
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Absorption and Transport of Carotenoids
"[Carotene] absorption can be very low, i.e., as low as 1-2% from raw, uncooked vegetables such as the carrot.2"
"Particle size of uncooked foods is particularly important; pureed or finely chopped vegetables yield considerably higher b-carotene absorption compared to whole or sliced raw vegetables.2,3"
"Dietary fat stimulates bile flow from the gall bladder which facilitates the emulsification of fat and fat-soluble vitamins into lipid micelles within the small intestine. Without micelle formation, carotenoids are poorly absorbed. Several researchers have shown that the absence of dietary fat or very low levels of fat in the diet substantially reduces human carotene absorption.4-15,16-18 For example, Roels et al.17 showed that in boys with vitamin A deficiency in an African village, supplementation of their carotene-sufficient but low-fat diets (about 7% of calories) with 18 gm/day of olive oil substantially improved carotene absorption (from less than 5% to 25%)."
"Some forms of dietary fiber may also inhibit carotenoid utilization, perhaps by reducing lipid micelle formation.19,20 Rock and Swendseid20 recently found that when 12 grams of citrus pectin was added to a control meal containing 25 mg p-carotene, the plasma b-carotene response in female subjects was significantly reduced."
--
beta-carotene intestinal absorption: bile, fatty acid, pH, and flow rate effects on transport | Gastrointestinal and Liver Physiology
"The lack of significant influence of sodium taurocholate’s concentration on b-carotene absorption by the small intestine would suggest that once the detergent properties of bile salts are fulfilled by achieving the critical micellar concentration, further increase in their concentration does not facilitate p-carotene’s absorption rate."
"The absorption rate of b-carotene increased in the presence of fatty acids and was highest when the monounsaturated long-chain fatty acid, oleic acid, was present in the perfusate (Table 4)." "Moreover, an increased absorption rate of b-carotene was noted after the addition of short- and medium-chain fatty acids that would not expand the micelle."
"Absorption of b-carotene in the presence of polyunsaturated fatty acids (linoleic and linolenic) was lower than in the presence of the monounsaturated fatty acid (oleic acid) (Table 4)."
"Similar decrease in retinol (9) and vitamin K1, (10) absorption in the presence of polyunsaturated fatty acids in the infusate has been previously noted."
--
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC292843/pdf/jcinvest00268-0107.pdf
--
Questions should be addressed to burtlan with tenderness.
@Makrosky - I suppose that this reads better, right? Please force charlie to bring back the yellow highlighter, it's way more aggressive.
In short:
- Carotene is much more difficult to be absorbed from plants in their raw state, they're better absorbed from supplements because they lack the matrix that holds it inaccessible, and cooking in turn makes it more available.
- Just a little dietary fat is enough to allow you to absorb plenty of carotenes, and even in the absence of fat it's possible to absorb if an excess is being ingested, possibly through bile.
- Meals interact, so if you ate plenty of cooked greens on your previous meal for example, and something fatty on the following meal, it's enough to absorb a great deal of the carotenes that remain in the intestines for longer than expected.
- A vitamin A deficiency increases your capacity to absorb carotenes.
--
Influence of Dietary Fat on β‐Carotene Absorption and Bioconversion into Vitamin A
"[..]only a limited amount of fat (3 g) is needed for optimal uptake of a- and b-carotene was the conclusion from studies by Roodenburg et al.7 who measured these carotenes in the plasma of 18- to 70- year-old Dutch subjects (n=14) consuming a low-fat (3 g) or a high-fat (36 g) spread enriched with 8 mg of a- plus b-carotene."
"[..]increases in a- and b-carotene were not different in subjects fed low-fat (315% and 139% increase, respectively) or highfat spreads (226% and 108% increase, respectively)."
"Dimitrov et al.8 studied the effects of dietary fat on the bioavailability of b-carotene supplements in healthy U.S. men and women who were 21 to 63 years of age."
"In the group not fed fat together with the b-carotene capsule, smaller plasma b-carotene elevations occurred, with levels being signicantly different from baseline only after 13 to 15 days of treatment; when b-carotene treatment was discontinued, b-carotene levels returned to baseline values 7 to 23 days later."
"In the study by Prince and Frisoli,9 no detectable changes in serum b-carotene were observed in three healthy volunteers (30 –36 years of age) who ingested a single 51-mg dose of b-carotene in the absence of dietary fat."
"As already mentioned, among vitamin A–malnourished children, increases in serum carotenes3 and retinol3,4 were seen when carotene-rich plant foods were ingested even in the absence of fat; these increases were similar to those observed when fat was provided with plant carotenes in the same meal. Among well nourished adults, Dimitrov et al.8 also reported small increases in plasma b-carotene when daily b-carotene supplements were ingested for 3 weeks with a fat-free breakfast followed by a low-fat (6 g fat) midday meal. It is logical to presume that in order for maximal carotene utilization to take place, the fat and carotene sources should be provided in the same meal. When dietary fat is not provided together with b-carotene, however, it is possible that delayed gastric emptying of b-carotene and/or delayed intestinal uptake and release of -carotene into the lymphatic and then blood circulation may occur, provided intraluminal lipids become available from the next meal to allow packaging of b-carotene into chylomicrons. That delayed release of b-carotene from enterocytes can take place is supported by data from human studies.27,28 The timing between the ingestion of -carotene and dietary fat cannot be too far apart, however. Henderson et al.27 reported that in a subject who did not consume food until 16 hours after the b-carotene dose, no increase in serum b-carotene was seen. Perhaps the reverse may also be possible: that some fat from a previous meal may remain in the intestines to aid in the absorption of b-carotene ingested hours later."
"Another possible explanation for b-carotene utilization in the absence of dietary fat is that endogenously secreted fat in the bile may play a role in b-carotene absorption. It is known that bile salts promote vesicular secretion of lecithin and cholesterol into bile, and that the secreted vesicles dissolve into mixed micelles in biles enriched with more hydrophobic bile salts.29 The importance of bile and bile salts in stimulating the absorption of b-carotene from the gastrointestinal tract is well documented.30–32"
"To explain b-carotene absorption in the absence of dietary fat, it has been suggested by Dimitrov et al.8 that the chylomicron–lymphatic system may not be the only pathway for b-carotene transport in humans. Likewise, Borel et al.28 speculated on the possibility of a greater transport of b-carotene via the portal pathway in the presence of medium-chain triglycerides."
"De Pee et al.33 reported that carotenes in orange fruit are more bioavailable than those in green leafy vegetables and carrots because b-carotene molecules in fruit are present in lipid droplets in chromoplasts and can be readily released during digestion. In green leaves, b-carotene molecules are complexed with proteins located in cell chloroplasts and may be more dif cult to release from the matrix; carotenes in carrots exist as crystals, which may not be readily solubilized and absorbed."
It's a matter of amount, though.
"The type of dietary fat may influence the bioavailability of b-carotene from foods and supplements. However, studies with animals have produced conflicting results regarding the effect of different types of fat on b-carotene absorption and metabolism.37–42"
"b-carotene and retinyl palmitate responses in chylomicrons were markedly diminished when b-carotene was provided in a meal with medium-chain triglycerides than when b-carotene was provided with long-chain triglycerides, apparently owing to the lack of secretion of triglyceride-rich chylomicrons in response to dietary medium-chain triglycerides."
"Based on serum retinol or b-carotene responses to meals containing carotenes and different amounts of fat, it has been suggested that only a small amount of fat may be required to ensure carotene utilization in humans — 5 g of fat in a meal containing 40 g of cooked spinach (with ~1.2 mg b-carotene)4[reference] or 3 g of fat for 8 mg of burtlan- plus b-carotene supplements consumed with a meal.7"
--
Absorption and Transport of Carotenoids
"[Carotene] absorption can be very low, i.e., as low as 1-2% from raw, uncooked vegetables such as the carrot.2"
"Particle size of uncooked foods is particularly important; pureed or finely chopped vegetables yield considerably higher b-carotene absorption compared to whole or sliced raw vegetables.2,3"
"Dietary fat stimulates bile flow from the gall bladder which facilitates the emulsification of fat and fat-soluble vitamins into lipid micelles within the small intestine. Without micelle formation, carotenoids are poorly absorbed. Several researchers have shown that the absence of dietary fat or very low levels of fat in the diet substantially reduces human carotene absorption.4-15,16-18 For example, Roels et al.17 showed that in boys with vitamin A deficiency in an African village, supplementation of their carotene-sufficient but low-fat diets (about 7% of calories) with 18 gm/day of olive oil substantially improved carotene absorption (from less than 5% to 25%)."
"Some forms of dietary fiber may also inhibit carotenoid utilization, perhaps by reducing lipid micelle formation.19,20 Rock and Swendseid20 recently found that when 12 grams of citrus pectin was added to a control meal containing 25 mg p-carotene, the plasma b-carotene response in female subjects was significantly reduced."
--
beta-carotene intestinal absorption: bile, fatty acid, pH, and flow rate effects on transport | Gastrointestinal and Liver Physiology
"The lack of significant influence of sodium taurocholate’s concentration on b-carotene absorption by the small intestine would suggest that once the detergent properties of bile salts are fulfilled by achieving the critical micellar concentration, further increase in their concentration does not facilitate p-carotene’s absorption rate."
"The absorption rate of b-carotene increased in the presence of fatty acids and was highest when the monounsaturated long-chain fatty acid, oleic acid, was present in the perfusate (Table 4)." "Moreover, an increased absorption rate of b-carotene was noted after the addition of short- and medium-chain fatty acids that would not expand the micelle."
"Absorption of b-carotene in the presence of polyunsaturated fatty acids (linoleic and linolenic) was lower than in the presence of the monounsaturated fatty acid (oleic acid) (Table 4)."
"Similar decrease in retinol (9) and vitamin K1, (10) absorption in the presence of polyunsaturated fatty acids in the infusate has been previously noted."
--
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC292843/pdf/jcinvest00268-0107.pdf
--
Questions should be addressed to burtlan with tenderness.
@Makrosky - I suppose that this reads better, right? Please force charlie to bring back the yellow highlighter, it's way more aggressive.
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