Plants in Human Nutrition, Diet, and Health PDF

# Plants in Human Nutrition, Diet, and Health ## Outline * Nutrition from food * Macromolecules * Carbohydrates * Lipids * Proteins * Vitamins & Minerals * Bioactive Molecules * The Intestinal Microbiome * Vegetarian, Vegan, Organics ## Nutrition from food * nutrients: substances that are necessary for the body's growth, maintenance, and function which must be obtained from food 1. carbohydrates 2. 3. amino acids 4. vitamins 5. minerals ## You are what you … ingest * ~ 65% water * ~ 35% other molecules Living tissues and organs (both plant and animal) are 60-70% water… …and contain four classes of macromolecules in different proportions. Most living plant tissues are composed of 80-90% cell wall polysaccharides. ### Macromolecules * large, often complex chains (polymers) of molecules created by the bonding together (polymerization) of individual units called monomers 1. Carbohydrates 2. 3. Lipids ## Energy vs. Nutrients * **Energy requirements** * Measured in calories * Harvested by removing energy from chemical bonds * **Nutrient requirements** * Amount of each nutrient required by most people should be higher than the established minimum * **How were these determined?** * Clinical trials, quasi-experimental, animal studies, cohort studies… and from all of these, meta-analysis (lots of scientific research) ## TABLE 3.1: How humans use food energy | Food | Food energy supplied (calories) | Time required to use food energy (hours) | |---|---|---| | 6 oz (200 g) yogurt | 130 | Resting: 1.5 | Walking: 0.5 | Running: 0.2 | | Cheeseburger | 530 | Resting: 6.0 | Walking: 1.5 | Running: 1.0 | | 10-in (25 cm) pizza | 1300 | Resting: 15.0 | Walking: 4.0 | Running: 2.0 | PLANTS, GENES & AGRICULTURE 1e, Table 3.1 © 2018 Oxford University Press ## Macromolecules * large, often complex chains (polymers) of molecules created by the bonding together (polymerization) of individual units called monomers 1. Carbohydrates 2. 3. Lipids ## Carbohydrates - heavy energy molecules * All sugars * loosely defined as molecules that contain carbon, hydrogen, and oxygen in a 1:2:1 ratio (CH2O)n * Monomer = "monosaccharides", simple sugars * e.g. glucose; fructose * Polymer = "polysaccharides" * Disaccharide eg. glucose + fructose = sucrose * Storage: starch * Structural: cellulose ## Monosaccharides: (CH2O)x * Named based on the number of carbons * x = 3 = glyceraldehyde * x = 5 = pentoses * x = 6 = hexoses (B) | Three-carbon sugar | Five-carbon sugars (pentoses) | Six-carbon sugars (hexoses) | |---|---|---| | H1 C2 н-с-он3 н-с-он H | 5 CH2OH OH5 C Ο H OH 4 C1\H H H H OH 3|C2 H OH | 6 CH2OH OH5 C Ο H OH 4 C1\H H H H OH3 CH2OH2 C OH1 | | Glyceraldehyde | Ribose | a-Galactose | | | Deoxyribose | Fructose | PLANTS, GENES & AGRICULTURE 1e, Figure 3.3 (Part 2) ©2018 Oxford University Press ## Monosaccharides: (CH2O)x * Often form rings with oxygen as a member (displaces one carbon out of the ring) (A) | Aldehyde group | Oxygen bridge | a Orientation | ẞ Orientation | |---|---|---|---| | HC2 H-с-ОН3 HO-C-H4 H-C-он5 H-C-он6 H | 6 CH2OH OH5 C H OH4 C1 OH HO C2 H3 OH | 6 CH2OH OH5 C H OH4 C1 OH HO C2 H3 OH | | | Straight-chain form | | a-Glucose | B-Glucose | PLANTS, GENES & AGRICULTURE 1e, Figure 3.3 (Part 1) © 2018 Oxford University Press ## Starch is used for storage, cellulose is used for structure, both are polymers of glucose - biochemistry matters! * Alpha 1,4 bond * starch * hydration causes it to form an open spiral; easy for enzymes to get in and hydrolyze * Beta 1,4 bond * cellulose * β-bond causes the monosaccharides to flip; forms a rod and is much less accessible to enzymes because adjacent chains bond together (insoluble) ## Lipids-light-weight energy molecules * All are insoluble in water * fats, oils, sterols * e.g. triglycerides; cholesterol, phospholipids * triglycerides and phospholipids both have glycerol and fatty acids * saturated or unsaturated ## (B) Triglycerides (oils and fats)_(C) Phospholipids | Triglycerides | Phospholipids | |---|--- | CH2 -CH -CH2 | (CH3)3N CH2-CH -CH2 CH2 | CH2 Glycerol O O 0 0 C C C O Fatty acid "tails" | Choline | O O 00 | C C C O | Hydrophobic fatty acid "tails" | Phosphate -O-P=0 Glycerol O 00 | C C C O | Diglyceride | | (D) Sterols | Sterols | | | --- | --- | | H3CO | OH H3C CH3 | H3C H3CO | CH3 | H3C HO | HO Cholesterol, found in | Brassinolide, many membranes | a plant hormone | | * Extracellular * Intracellular * Phospholipid bilayer * Hydrophobic tail * Hydrophilic head ## Lipids- light-weight energy molecules * All are insoluble in water * fats, oils, sterols * e.g. triglycerides; cholesterol, phospholipids * triglycerides and phospholipids both have glycerol and fatty acids * saturated or unsaturated ## Saturated Fats * Single bonds between carbons * Mainly solid at room temperature ## Unsaturated fats * One or more double bonds between carbons * Mainly liquid at room temperature ## Hydrogenation * Technique to make oils more "firm" and less prone to oxidation (breakdown) * longer storage * flavour and texture * Artificial process can lead to trans-fats ## Some fatty acids are "essential" * (cannot be made with human metabolism) * 2-3: linolenic – 2 unsaturated bonds - from flax, canola, safflower, some oily fish, nuts * 2-6: linoleic acid – 3 unsaturated bonds - from chicken, plant oils ## Too much energy – a bad thing? The expenditure of energy in adult humans comprises two main components: 1. Basal metabolism – metabolism performed as part of daily maintenance and normal growth – ~ 1600 calories a day 2. Active metabolism - Conscious muscle movements * Affluence and sedentary lives have led to new challenges: * obesity * heart disease: syndrome ## Government suggestions * Based on science, availability, economics, and … * Canada food guide was revised in 2019. * https://food-guide.canada.ca/en/ * Input from industry is forbidden * “Eat food. Not too much, Mostly plants.” * Michael Pollan, 2009 In defense of food. ## Proteins - “structure molecules" * Contain a lot of nitrogen * Monomer = acids * e.g. glycine, tryptophan * Basic structure: * amino * carboxyl (carboxylic acid) * "R" group (provides distinctive traits) * Polymer = "polypeptides” (proteins) * 3-D structure allows these to form enzymes, pigments, storage structures ... all the cool stuff. ## Protein assimilation * Essential amino acids (9) * must be obtained from food * amino acids come in the form of proteins * due to their varied structures and chemical properties, some proteins are less digestible than others ## TABLE 3.2: The 20 amino acids | Essential (Must be obtained from food) | Non-essential (can be synthesized by the human body) | |---|---| | Histidine (His) | Alanine (Ala) | | Isoleucine (lle) | Arginine (Arg) | | Leucine (Leu) | Asparagine (Asn) | | Lysine (Lys) | Aspartic acid (Asp) | | Methionine (Met) | Cysteine (Cys) | | Phenylalanine (Phe) | Glutamic acid (Glu) | | Threonine (Thr) | Glutamine (Gln) | | Tryptophan (Trp) | Glycine (Gly) | | Valine (Val) | Proline (Pro) | | | Serine (Ser) | | | Tyrosine (Tyr) | ## Protein Score * based on digestibility and what essential a they have * some cultures use complementary foods to adjust ## Vitamins * Small, organic molecules that aren't macromolecules (or their monomers) that must be eaten * Some foods are richer than others Four ways to prevent vitamin deficiencies: 1. balanced diet 2. vitamin supplements 3. foods 4. genetically engineered plants ## The strange case of 'Vitamin D' * cholecalciferol * formed from cholesterol via sunlight * seems to act as a chemical messenger rather than to assist enzyme functions (therefore a hormone) * many people don't get enough sunlight * deficiency is associated with rickets, cancer, heart disease, diabetes, autoimmune disorders * other sources include cod liver oil, supplements, and fortified foods ## Minerals * Obtained through food and the water we drink * “micronutrients” ## TABLE 3.3: Some mineral requirements in the human diet | Mineral | RDA (mg) | Functions | |---|---|---| | Calcium | 1000-1300 | Bone and tooth formation | | Phosphorus | 700-1250 | Bone and tooth formation; some metabolic functions| | Magnesium | 320-400 | Bone formation, enzyme activation | | Sodium | 1500 | Bone, electrolyte formation | | Chloride | 2300 | Electrolyte formation | | Potassium | 4700 | Electrolyte formation | | Iron | 8-18 | Hemoglobin, enzyme formation | | Zinc | 12-15 | Enzyme, insulin formation | | Copper | 1.5-3 | Enzyme formation | | Iodine | 0.15 | Thyroxine formation | | Manganese | 2.5-5 | Enzyme formation | | Selenium | 0.04-0.07 | Fat metabolism | | Chromium | 0.05 | Glucose metabolism | | Molybdenum | 0.035 | Enzyme activity | ## Bioactive Molecules * Plant biochemistry is much more sophisticated than that of animals * Animals can move around to find food, avoid toxins, evade predators * Plants use to compensate for being sedentary - often have larger genomes encoding a variety of metabolic paths ## Metabolites | Metabolites | Examples | |---|---| | Primary | | | Enzymes | protease, lipase, peroxidase | | Amino acid | proline, leucine | | Organic acid | acetic acid, lactic acid | | Vitamins | A, B, C | | Secondary | | | Pigments | carotenoids, anthocyanins | | Alkaloids | morphine, codeine | | Essential oil | lemon grass oil, rose oil | | Toxins |abrin, ricin | | Lectins | concanavalin A | | Drugs | vinblastin, curcumin | | Polymeric substances | rubber, gums, cellulose | ## "Superfoods" * Antioxidants * supposed to help eliminate highly reactive oxygen molecules (often called free radicals) * no studies that show antioxidants consistently reduce DNA damage or cancer risk * Functional foods * may be supplemented (“fortified") ## The Intestinal Microbiome | Microbiome | Microbiome | |---|---| | Gemella, Veillonella, Neisseria, Fusobacterium, Streptococcus, Prevotella, Pseudomonas, Actinomyces | Streptococcus., Prevotella, Veillonella, Haemophilus, Rothia | | Lactobacillus, Streptococcus, Prevotella, Veillonella, Escherichia, Enterococcus, Bacteroides., Clostridium | Streptococcus, Bacillus, Enterobacter, Leptotrichia, Veillonella, Pseudomonas, Helicobacter | | Lactobacillus, Streptococcus, Prevotella, Lachnospiraceae, Ruminococcus, Enterobacter, Bacteroides, Clostridium, AKkermansia | ## Probiotic Bacteria Types or species of bacteria in the human microbiome that are beneficial or essential for proper health Can you think of any foods that could be considered probiotics? ## Diets * Not one diet is a magic cure for everything * Nutritional Deficiencies can lead to acute or chronic health issues * enzymes, organ damage, interactions all affect the complex network of feedback loops that are part of our metabolism * Vegetarians and Vegans * often use legumes (13% of humanity's protein) * Cannot obtain vitamin B12 (easily obtained from meats, but can come from microorganisms) * Organic foods – more about ecology than health ## Next class * Plant Domestication and Biotechnology ## Study Guide from Chapter * List the four macromolecule classes used by biologists. * Describe the human health implications of the macromolecule classes. * Identify (by sight and by listing) the monomers that assemble to form each macromolecule class. * Describe the importance of nitrogen in forming proteins. * Describe the atoms involved in creating carbohydrates. * Distinguish between vitamins and the macromolecule classes. * Explain how diseases can form from nutritional deficiencies. * Explain how particular choices of diet keep people healthy by paying attention to consumption of specific food types. * Describe forms of evidence regarding the benefits or drawbacks of organic food production. * Define key terms of the chapter.

Plants in Human Nutrition, Diet, and Health PDF

Document Details

Tags

Related

Summary

Full Transcript

Upgrade to continue