how bread causes a deficiency of biotin,
Biotin deficiency and the case of Lindow Man
Lindow Man, whose preserved body was found in a peat bog in Cheshire, England in 1984, is one of the more extensively studied of the so-called "bog mummies" [Stead, Bourke, and Brothwell 1986]. The principal last meal of Lindow Man likely consisted of a non-leavened whole-meal bread probably made of emmer wheat, spelt wheat, and barley. Unleavened whole-grain breads such as this represented a dietary staple for most of the less-affluent classes during this time. Excessive consumption of unleavened cereal grains negatively impacts a wide variety of physiological functions which ultimately present themselves phenotypically (i.e., via changes in physical form or growth). The well-documented phytates of cereal grains sequester many divalent ions including calcium, zinc, iron, and magnesium, which can impair bone growth and metabolism. Further, there are antinutrients in cereal grains which directly impair vitamin D metabolism [Batchelor 1983; Clement 1987]; and rickets are routinely induced in animal models via consumption of high levels of cereal grains [Sly 1984].
Less well-appreciated are the ability of whole grains to impair biotin metabolism. My colleague, Bruce Watkins [Watkins 1990], as well as others [Blair 1989; Kopinksi 1989], have shown that biotin deficiencies can be induced in animal models by feeding them high levels of wheat, sorghum, and other cereal grains. Biotin-dependent carboxylases are important metabolic pathways of fatty-acid synthesis, and deficiencies severely inhibit the chain-elongation and desaturation of 18:2n6 (linoleate) to 20:4n6 (arachidonic acid). Human dietary supplementation trials with biotin have shown this vitamin to reduce fingernail brittleness and ridging that are associated with deficiencies of this vitamin [Hochman 1993].
Careful examination of the photograph of Lindow's man fingernail (still attached to a phalange of the right hand [Stead 1986, p. 66]) shows the characteristic "ridging" of biotin deficiency. It is likely that regular daily consumption of high levels (>50% daily calories) of unleavened cereal-grain breads, which Lindow man may have consumed, caused a biotin deficiency, which in turn caused nail ridging.
Biotin deficiency and the case of Lindow Man
Lindow Man, whose preserved body was found in a peat bog in Cheshire, England in 1984, is one of the more extensively studied of the so-called "bog mummies" [Stead, Bourke, and Brothwell 1986]. The principal last meal of Lindow Man likely consisted of a non-leavened whole-meal bread probably made of emmer wheat, spelt wheat, and barley. Unleavened whole-grain breads such as this represented a dietary staple for most of the less-affluent classes during this time. Excessive consumption of unleavened cereal grains negatively impacts a wide variety of physiological functions which ultimately present themselves phenotypically (i.e., via changes in physical form or growth). The well-documented phytates of cereal grains sequester many divalent ions including calcium, zinc, iron, and magnesium, which can impair bone growth and metabolism. Further, there are antinutrients in cereal grains which directly impair vitamin D metabolism [Batchelor 1983; Clement 1987]; and rickets are routinely induced in animal models via consumption of high levels of cereal grains [Sly 1984].
Less well-appreciated are the ability of whole grains to impair biotin metabolism. My colleague, Bruce Watkins [Watkins 1990], as well as others [Blair 1989; Kopinksi 1989], have shown that biotin deficiencies can be induced in animal models by feeding them high levels of wheat, sorghum, and other cereal grains. Biotin-dependent carboxylases are important metabolic pathways of fatty-acid synthesis, and deficiencies severely inhibit the chain-elongation and desaturation of 18:2n6 (linoleate) to 20:4n6 (arachidonic acid). Human dietary supplementation trials with biotin have shown this vitamin to reduce fingernail brittleness and ridging that are associated with deficiencies of this vitamin [Hochman 1993].
Careful examination of the photograph of Lindow's man fingernail (still attached to a phalange of the right hand [Stead 1986, p. 66]) shows the characteristic "ridging" of biotin deficiency. It is likely that regular daily consumption of high levels (>50% daily calories) of unleavened cereal-grain breads, which Lindow man may have consumed, caused a biotin deficiency, which in turn caused nail ridging.