227
reduce the levels of high-sensitivity C-reactive protein in the serum (Ouellet et al.
2008) and increase insulin sensitivity in subjects resistant to insulin (Ouellet
et al. 2007).
Biopeptides extracted from seafood proteins have an immense influence on the
promotion of healthy eating. In a placebo-controlled trial, the administration of
valyl-tyrosine, a peptide extracted from sardines, has resulted in a decrease of
9.3 mmHg in the systolic blood pressure and a decrease of 5.2 mmHg in the diastolic blood pressure (Kawasaki et al. 2000). Moreover, marine bioactive peptides
isolated from the jumbo squid were seen to inhibit lipid peroxidation. Their activity
was similar to butylated hydroxytoluene (BHT), but much lower in comparison with
α-tocopherol (Mendis et al. 2005). According to previously stated work by several
authors, marine bioactive peptides have ameliorated hypocholesterolemia
(Wergedahl et al. 2004) and have displayed immunomodulatory (Duarte et al. 2006)
and antimicrobial effects (Tincu and Taylor 2004), both in animals and in vitro.
However, the health benefits of marine proteins need further investigation in studies
conducted on humans.
13.1.5 Vitamin D
In addition to its valuable protein and lipid composition, seafood also comprises
considerable amounts of vitamin D (Holick 2008). Rickets, low bone density,
osteomalacia and osteoporosis are health conditions associated with vitamin D
deficiency (Cranney et al. 2007). Fan and his coworkers (2013) reported an
inverse relation among fish consumption and chances of hip fracture in the
Chinese elderly. Alongside to bone-related disorders, vitamin D deficiency seems
to be also involved in the development of diabetes, autoimmune disorders, aggressive cancers, as well as CVD (Holick 2008). Sunlight exposure is a key element
in vitamin D homeostasis. Limited sun exposure has been linked to vitamin D
deficiency (Norman 2008). Overall, the average dietary intake of vitamin D is of
at least 1000 international units (IU) or equivalent to 25 mg per day (Lu et al.
2007; Holick 2008). Vitamin D 2 (ergocalciferol) is found in plants such as mushrooms, whereas vitamin D 3 (cholecalciferol) is found in fish and is also produced
in the skin via exposure to ultraviolet B rays (Holick 2008; Norman 2008).
Ergocalciferol slightly differs in structure from cholecalciferol, as it contains one
additional double bond along with methyl group. In various species of fish muscle, the vitamin D content ranges from 5 to 30 mg/100 g (Mattila et al. 1995). It
was observed that wild salmon has a higher content of vitamin D as compared to
farmed salmon. Moreover, the methods of preparation also affect the final quantity of vitamin D. After frying, 50% of the vitamin D is retained in the salmon (Lu
et al. 2007).
13 Nutritional and Health Benefits of Seafoods
reduce the levels of high-sensitivity C-reactive protein in the serum (Ouellet et al.
2008) and increase insulin sensitivity in subjects resistant to insulin (Ouellet
et al. 2007).
Biopeptides extracted from seafood proteins have an immense influence on the
promotion of healthy eating. In a placebo-controlled trial, the administration of
valyl-tyrosine, a peptide extracted from sardines, has resulted in a decrease of
9.3 mmHg in the systolic blood pressure and a decrease of 5.2 mmHg in the diastolic blood pressure (Kawasaki et al. 2000). Moreover, marine bioactive peptides
isolated from the jumbo squid were seen to inhibit lipid peroxidation. Their activity
was similar to butylated hydroxytoluene (BHT), but much lower in comparison with
α-tocopherol (Mendis et al. 2005). According to previously stated work by several
authors, marine bioactive peptides have ameliorated hypocholesterolemia
(Wergedahl et al. 2004) and have displayed immunomodulatory (Duarte et al. 2006)
and antimicrobial effects (Tincu and Taylor 2004), both in animals and in vitro.
However, the health benefits of marine proteins need further investigation in studies
conducted on humans.
13.1.5 Vitamin D
In addition to its valuable protein and lipid composition, seafood also comprises
considerable amounts of vitamin D (Holick 2008). Rickets, low bone density,
osteomalacia and osteoporosis are health conditions associated with vitamin D
deficiency (Cranney et al. 2007). Fan and his coworkers (2013) reported an
inverse relation among fish consumption and chances of hip fracture in the
Chinese elderly. Alongside to bone-related disorders, vitamin D deficiency seems
to be also involved in the development of diabetes, autoimmune disorders, aggressive cancers, as well as CVD (Holick 2008). Sunlight exposure is a key element
in vitamin D homeostasis. Limited sun exposure has been linked to vitamin D
deficiency (Norman 2008). Overall, the average dietary intake of vitamin D is of
at least 1000 international units (IU) or equivalent to 25 mg per day (Lu et al.
2007; Holick 2008). Vitamin D 2 (ergocalciferol) is found in plants such as mushrooms, whereas vitamin D 3 (cholecalciferol) is found in fish and is also produced
in the skin via exposure to ultraviolet B rays (Holick 2008; Norman 2008).
Ergocalciferol slightly differs in structure from cholecalciferol, as it contains one
additional double bond along with methyl group. In various species of fish muscle, the vitamin D content ranges from 5 to 30 mg/100 g (Mattila et al. 1995). It
was observed that wild salmon has a higher content of vitamin D as compared to
farmed salmon. Moreover, the methods of preparation also affect the final quantity of vitamin D. After frying, 50% of the vitamin D is retained in the salmon (Lu
et al. 2007).
13 Nutritional and Health Benefits of Seafoods