Study Links
| Num | Year | Site | Note | |||
|---|---|---|---|---|---|---|
Estrogen
4.3 Fats
Hyper-Sanity/Hyper-Ethics/Vegan/Vegan Studies/Meat Studies/ Vegan Diet NMCD Journal > ^VD-Insulin1
Plant-based diets are typically low in saturated fat and cholesterol [28]. The lower fat content of V diets than OMN diets is responsible for a lower energy density and a drop in energy intake [21,23] and can also help to control blood lipid levels [29]. Monounsaturated fats have been associated with decreased LDL-C and increased resistance to oxidation of LDL-C [30]. Plant sterol intake reduces cholesterol absorption by binding cholesterol and bile acids [25].
The lower saturated fatty acid and higher polyunsaturated fatty acid consumption in V, compared with OMN diets, has also been associated with lower BP [21,31,32].
It has been suggested that the relatively low ratio of saturated to unsaturated fat in most V diets can exert a favorable impact on insulin sensitivity and beta-cell lipotoxicity [33].
V diets generally have higher content of plant foods, hence of complex carbohydrate, fiber, polyunsaturated fatty acids, and several micronutrients (e.g., magnesium and potassium) and phytochemicals [10,11],
whose beneficial synergistic combinations have been associated with a reduced incidence of many pathological conditions such as overweight, T2D, and hypercholesterolemia [12–16].
Diets emphasizing the consumption of whole plant foods have also been associated with lower oxidative stress, inflammation, better endothelial function, and increased insulin sensitivity [17–19].
Hence, it is possible that the beneficial effects of a plant-based diet derive from the increased content of healthy compounds, mainly present in plant foods, and the reduced or absent content of some harmful factors (mentioned above), mainly contained in animal foods. It is also worth emphasizing here that the mitigation of the -often- coexisting pathological conditions, can be considered among the most important mechanisms.
BCAA’s
Branched-chain amino acids (BCAAs), higher in OMN diets, could persistently activate the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway, inhibiting glucose transport into insulin-sensitive tissues, including muscle and fat tissues [36].
BCAAs can promote the accumulation of myotoxic metabolites, that can increase β-cell mitochondrial dysfunction and stimulate stress kinase signaling, β-cell apoptosis and insulin resistance due to serine phosphorylation of insulin receptor substrate 1 [36].
Non-essential amino acids, which predominate in plant protein, have a greater impact on glucagon secretion than the essential ones. Acting on hepatocytes, glucagon can promote (and insulin inhibit) cAMP-dependent mechanisms that down-regulate lipogenic enzymes and cholesterol synthesis, while up-regulating hepatic LDL receptors and production of the insulin-like growth factor-1 ( IGF-I ) antagonist [34].
Arginine
Oral administration of arginine, abundant in plant proteins, has been shown to improve insulin sensitivity in individuals with T2D in randomized, long-term trials [40].
A lower sulfur amino acid intake, which relies on plant-derived protein sources rather than meat-derived foods, has been associated with reduced risk for cardiometabolic diseases in a recent analysis from the Third National Examination and Nutritional Health Survey (NHANES III) Study (1988–1994) [41].
4.6 Iron
Plant iron (non-heme iron) is not as easily absorbed as iron from meat (heme iron), for which heme iron can lead to higher ferritin levels.
High iron tissue concentration can contribute to increase glucose production, hepatic glucose output, and to decrease glucose utilization [44].
Iron can promote the formation of the highly reactive oxygen species (ROS), hence increasing cellular oxidative stress, which in turn can inhibit insulin binding.
Moreover, ROS can damage pancreatic β-cells, impair insulin-stimulated IRS-1 tyrosine phosphorylation, decrease phosphoinositide 3-kinase, and inhibit the translocation of glucose transporter type 4 (GLUT4) to the plasma membrane.
It has been shown that iron stores in pancreatic β-cells can lead to impaired insulin secretion. Moreover, high hepatic iron stores can interfere with hepatic insulin extraction and increased hepatic glucose output [44].
Evidence has emerged from cross-sectional studies of a link between increased serum ferritin concentrations and MetS [45].
In V, significantly lower (although still normal) concentrations of serum ferritin have been reported than in OMNs [46–48]. These factors may be beneficial for glycemic control and MetS risk as well.