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anticoagulation and promote bleeding in patients taking anticoagulant medications
such as warfarin (Gross et al. 2017).
3.7.3 Protein Powders and Infant Formula as Supplements
Protein powders consisting of the dairy proteins casein and whey and of vegetable
proteins in soy protein isolate (SPI) are popular supplements among athletes and
body builders. These proteins are also the basis of infant formulas. The dairy proteins appear to have little toxicity except in individuals with allergies to cow’s milk
protein, although excessive consumption may result in ketosis. In contrast, there is
an ongoing debate with regard to the potential safety of SPI. This debate is related
primarily to the presence of weakly estrogenic compounds—the isoflavones: genistein and daidzein, which are among the 100 phytochemicals that remain bound to
the protein isolate (Fang et al. 2004). These compounds can reach potentially estrogenic levels after SPI consumption in soy formula–fed infants and in children, men,
and postmenopausal women taking soy protein supplements. Concerns have focused
on potential estrogenic effects in early development resulting in reproductive toxicity, infertility, demasculinization, and increased promotion of estrogen-responsive
cancers such as breast and endometrial cancer (Messina,2016). Animal studies of
SPI and soy formula toxicity have however been contradictory. Akingbemi et al.
(2007) reported that perinatal exposure to diets made with soy resulted in suppressed steroidogenesis, decreased testosterone secretion, and increased Leydig cell
proliferation in rats. Similarly, marmoset monkeys fed soy infant formula had suppressed serum testosterone concentrations (Tan et al. 2006). Increased testis size
and increased Leydig cell numbers per testis were also observed in these monkeys
at adulthood, consistent with compensated Leydig cell failure. In adult female
ovariectomized mice, feeding SPI increased growth of human breast cancer cell
xenografts, consistent with an estrogenic effect (Allred et al. 2001). In contrast to
the small number of animal studies with SPI suggesting estrogenicity, lifetime feeding studies in rats fed with SPI revealed that the sole protein source in soy formulas
had no effects on sex organ weights, serum sex steroids concentrations, or fertility
(Badger et al. 2009).
3.7.4 Botanical Supplements
Traditional herbal medicine can be said to be the precursor both for drugs used in
modern medicine that are based on plant compounds (such as aspirin and morphine)
and for contemporary botanical dietary supplements. Herbal and botanical products
have sustained popularity given the fact that these natural (i.e., derived from plant
root, leaves, or bark) substances were among the oldest therapeutics. Estimates published by the CDC as part of the National Health and Nutrition Examination Survey
3 Dietary Supplements: Types, Health Benefits, Industry and Regulation
anticoagulation and promote bleeding in patients taking anticoagulant medications
such as warfarin (Gross et al. 2017).
3.7.3 Protein Powders and Infant Formula as Supplements
Protein powders consisting of the dairy proteins casein and whey and of vegetable
proteins in soy protein isolate (SPI) are popular supplements among athletes and
body builders. These proteins are also the basis of infant formulas. The dairy proteins appear to have little toxicity except in individuals with allergies to cow’s milk
protein, although excessive consumption may result in ketosis. In contrast, there is
an ongoing debate with regard to the potential safety of SPI. This debate is related
primarily to the presence of weakly estrogenic compounds—the isoflavones: genistein and daidzein, which are among the 100 phytochemicals that remain bound to
the protein isolate (Fang et al. 2004). These compounds can reach potentially estrogenic levels after SPI consumption in soy formula–fed infants and in children, men,
and postmenopausal women taking soy protein supplements. Concerns have focused
on potential estrogenic effects in early development resulting in reproductive toxicity, infertility, demasculinization, and increased promotion of estrogen-responsive
cancers such as breast and endometrial cancer (Messina,2016). Animal studies of
SPI and soy formula toxicity have however been contradictory. Akingbemi et al.
(2007) reported that perinatal exposure to diets made with soy resulted in suppressed steroidogenesis, decreased testosterone secretion, and increased Leydig cell
proliferation in rats. Similarly, marmoset monkeys fed soy infant formula had suppressed serum testosterone concentrations (Tan et al. 2006). Increased testis size
and increased Leydig cell numbers per testis were also observed in these monkeys
at adulthood, consistent with compensated Leydig cell failure. In adult female
ovariectomized mice, feeding SPI increased growth of human breast cancer cell
xenografts, consistent with an estrogenic effect (Allred et al. 2001). In contrast to
the small number of animal studies with SPI suggesting estrogenicity, lifetime feeding studies in rats fed with SPI revealed that the sole protein source in soy formulas
had no effects on sex organ weights, serum sex steroids concentrations, or fertility
(Badger et al. 2009).
3.7.4 Botanical Supplements
Traditional herbal medicine can be said to be the precursor both for drugs used in
modern medicine that are based on plant compounds (such as aspirin and morphine)
and for contemporary botanical dietary supplements. Herbal and botanical products
have sustained popularity given the fact that these natural (i.e., derived from plant
root, leaves, or bark) substances were among the oldest therapeutics. Estimates published by the CDC as part of the National Health and Nutrition Examination Survey
3 Dietary Supplements: Types, Health Benefits, Industry and Regulation