All about fruitarianism with a long-term fruitarian, Lena

proteins

  • Calcium Requirement and Animal Protein

    One study found that 0.85 mg of calcium was lost for each gram (1 g) of protein in the diet. A meta-analysis of 16 studies in 154 adult humans on protein intakes up to 200 g found that 1.2 mg of calcium was lost in the urine for every 1g rise in dietary protein. A small but more focussed study showed a rise of 40 mg in urinary calcium when dietary animal protein was raised from 40 to 80 g. Urinary calcium to dietary protein ratio is 1 mg to 1g. The empirical observation that each 1 g of protein results in 1 mg of calcium in the urine agrees very well with the phosphorus content of animal protein (about 1 percent by weight).

    This means that a 40 g reduction in animal protein intake from 60 to 20 g would reduce calcium requirement by the same amount as a 2.3 g reduction in dietary sodium, i.e. from 840 to 600 mg

    How animal protein exerts its effect on calcium excretion is not fully understood. 

  • Calcium Intake and Bone Fracture Risk

    With the exception of calcium deficiency rickets in Nigeria, no satisfactory explanation has been found for the apparently low prevalence of osteoporosis in countries on low calcium intakes. On international comparisons on a larger scale, it is very difficult to separate genetic from environmental factors. Osteoporosis was largely a disease of affluent industrialized cultures. Hip fracture prevalence (and by implication osteoporosis) is consequently related to animal protein intake, but also, paradoxically, to calcium intake because of the strong correlation between calcium and protein intakes within and between societies. This could be explained if protein actually increased calcium requirement. 

    Fracture risk has recently been shown to be a function of protein intake in North American women. There is also suggestive evidence that hip fracture rates depend on protein intake, national income, and latitude. Vitamin D deficiency in hip fracture patients in the developed world was established. Such fractures can be successfully prevented with small doses of vitamin D and calcium. It is therefore possible that hip fracture rates may be related to protein intake, vitamin D status, or both.

  • Protein Structure, Cooked and Denatured Proteins

    Proteins are chains of amino acids. The sequence of amino acids in a chain is known as the primary structure of a protein. The chains fold up to form complex three dimensional shapes. The chains can fold on themselves locally (secondary structure) and wrap around themselves to form a specific three dimensional shape (tertiary structure).

    The secondary / tertiary structure of a folded protein is directly related to its function. For example, enzymes are proteins that catalyze reactions. They have binding sites that interact with other molecules. These binding sites are created through the folding of the amino acid chains that gives rise to the three dimensional shape of the enzyme.

    Denatured Protein

    Denaturation of proteins involves the disruption and possible destruction of both the secondary and tertiary structures. Since denaturation reactions are not strong enough to break the peptide bonds, the primary structure (sequence of amino acids) remains the same after a denaturation process. Denaturation disrupts the normal sheets in a protein and uncoils it into a random shape.

    Denaturation occurs because the bonding interactions responsible for the secondary structure (hydrogen bonds to amides) and tertiary structure are disrupted. In tertiary structure there are four types of bonding interactions between "side chains" including: hydrogen bonding, salt bridges, disulfide bonds, and non-polar hydrophobic interactions. which may be disrupted. 

    Proteins can be denatured through exposure to heat or chemicals. Denatured proteins lose their three dimensional structure and thus their function. 

    Digestion of Proteins and Cooking

    Protein digestion begins in the stomach, where the acidic environment favors protein denaturation. Denatured proteins are more accessible as substrates for proteolysis than are native proteins. The primary proteolytic enzyme of the stomach is pepsin, a nonspecific protease that is maximally active at pH 2. Thus, pepsin can be active in the highly acidic environment of the stomach, even though other proteins undergo denaturation there.

    Heat disrupts hydrogen bonds and non-polar hydrophobic interactions. This occurs because heat increases the kinetic energy and causes the molecules to vibrate so rapidly and violently that the bonds are disrupted

    Foods are cooked to denature the proteins to make it easier for enzymes to digest them. Cooking food denatures some of the proteins in it and makes digestion more efficient. Heating to denature proteins in bacteria and thus destroy the bacteria.

  • Raw Food Enzymes Are Digested

    William T. Jarvis, former professor of public health, founder of the National Council against Health Fraud (www.ncahf.org):

    “Enzymes are complex protein molecules produced by living organisms exclusively for their own use in promoting chemical reactions. Orally ingested enzymes are digested in the stomach and have no enzymatic activity in the eater.” 

    Andrea Giancoli, R.D., a spokesperson for the American Dietetic Association:

    Enzymes are proteins and proteins denature with heat, but those enzymes are denatured - and thus inactivated - when they reach our stomachs. Our stomach acids are designed to break down proteins very efficiently.”

  • Protein Intake in Older Age

    Respondents aged 50–65 reporting high protein intake had a 75% increase in overall mortality and a 4-fold increase in cancer death risk during the following 18 years. These associations were either abolished or attenuated if the proteins were plant derived.

    Conversely, high protein intake was associated with reduced cancer and overall mortality in respondents over 65, but a 5-fold increase in diabetes mortality across all ages.

  • USDA Tips for Vegetarians

    Tips for Vegetarians

    Vegetarian diets can meet all the recommendations for nutrients. The key is to consume a variety of foods and the right amount of foods to meet your calorie needs. Follow the food group recommendations for your age, sex, and activity level to get the right amount of food and the variety of foods needed for nutrient adequacy. Nutrients that vegetarians may need to focus on include protein, iron, calcium, zinc, and vitamin B12

  • WHO on Protein and Amino Acid Requirements

    Protein Requirement Recommendation

    The requirement indicated by the meta-analysis (a median requirement of 105 mg nitrogen/kg per day or 0.66 g/kg per day of protein) can be accepted as the best estimate of a population average requirement for healthy adults.

    General recommendation

    For adults, the protein requirement per kg body weight is considered to be the same for both sexes, at all ages, and for all body weights within the acceptable range. The value accepted for the safe level of intake is 0.83 g/kg per day, for proteins with a protein digestibility-corrected amino acid score value of 1.0. No safe upper limit has been identified... (p. 242)

    Range Body weight Safe level of protein intake (score 1.0)
    From 40 kg 33 g per day
    To 80 kg 66 gper day
  • Lysine and Leucine in Fruit Safou

    Concentrations of some essential amino acids in fruit safou (Dacryodes edulis), such as lysine and leucine, are comparable to concentrations found in eggs.

  • Lean Meat is Not Pure Protein

    "Lean meat" is a misleading term. I noticed many times in conversations that people who think that they eat "proteins" tend to think about this food group as an almost pure protein, a perfect set of essential amino acids. Especially if they consume so called "lean meats." 

    In beef (presented as "90% lean meat") - half of the calories are from fat (http://nutritiondata.self.com/facts/beef-products/6193/2). Even in the leanest bird meat approximately the fifth of the energy is from fat, ~18% in the leanest I could find (http://nutritiondata.self.com/facts/poultry-products/704/2).

    Digestibility-corrected amino acid score (PDCAAS) of protein in beef is only 0.92, chicken - 0.91(?), and egg whites and soy - 1 or 100% (not that it matters much). Note, that 62% of calories in a whole egg are from fat, and 40% in soybeans. 

Linus Pauling

I have something that I call my Golden Rule. It goes something like this: 'Do unto others twenty-five percent better than you expect them to do unto you.' … The twenty-five percent is for error.

Fungi

fungus is any member of the group of eukaryotic organisms that includes unicellular microorganisms such as yeasts and molds, as well as multicellular fungi that produce familiar fruiting forms known as mushrooms. These organisms are classified as a kingdom Fungi, which is separate from the other eukaryotic life kingdoms of plants and animals. Fungi do not use photosynthesis to create energy.

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