HORT10030: Intro to Plant-Based Diets

• HORT10030 is the course code
• The course is focused on Plant-based Diets for a Changing Climate
• The lectures are instructed by Dr Caroline Elliott-Kingston, from UCD Horticulture
• Lectures will be held Wednesdays 12:00-1:00 in G-08.AG and Thursdays 12:00-1:00 in G-15.AG

What is a Plant-Based Diet?

• A plant-based diet does not require being vegetarian or vegan and does not mean never eating meat, fish or dairy
• It does mean choosing proportionately more food from plant-based sources
• Plant-based eating patterns focus on foods primarily, but not exclusively, sourced from plants

Plant-Based Food Sources

• Fruits are the reproductive structures of plants that contain seeds
• Vegetables include roots, stems, shoot buds, and leaves
• Legumes are any plant from the Fabaceae family, including its leaves, stems, and pods
• Edible seeds from legumes are called pulses and include beans, lentils, and peas
• Beans are the seeds of several plants in the Fabaceae family
• Nuts are dry, single-seeded fruits with a high oil content
• Seeds are embryonic plants that can develop into fully grown plants
• Oils are fats taken from plants, usually from seeds
• Whole grains are grains of any cereal and pseudocereal that contain endosperm, germ, and bran, in contrast to refined grains, which only contain endosperm

Types of Plant-Based Diets (PBD)

• Mediterranean diets consist mostly of plant-based foods, along with fish, poultry, eggs, cheese, and yogurt a few times a week, with meats and sweets consumed less often
• Vegetarian diets, sometimes referred to as lacto-ovo vegetarian, include eggs and dairy but exclude meat, poultry, fish, and seafood
• Flexitarian diets, also known as semi-vegetarian, include eggs, dairy, and occasionally meat, poultry, fish, and seafood
• Pescatarian diets include eggs, dairy, fish, and seafood but exclude meat and poultry
• Vegan diets include no animal foods or animal-based foods
• Plant-based diets offer all the necessary protein, fats, carbohydrates, vitamins, and minerals for optimal health, and are often higher in fiber and phytonutrients
• Vegans are recommended to add a vitamin B12 supplement to ensure they receive all the nutrients they require

Essential Amino Acids

• Nine amino acids cannot be synthesized by humans and must be supplied through diet
• These amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine
• Not all plant-based proteins are complete proteins
• A complete protein contains adequate amounts of all nine essential amino acids
• Animal products like beef, fish, dairy, and eggs contain enough of every essential amino acid and are considered complete proteins
• Many plant sources of protein are too low in, or missing, one or more essential amino acids and are considered incomplete protein sources
• Plant foods contain varying amounts of amino acids, so getting enough of each essential amino acid throughout the day is possible by eating a varied diet and combining complementary plant proteins

Plant-Based Complete Proteins

• Soy protein is a complete protein, offering a source of lean, cholesterol-free, and lactose-free protein. Sources include tofu, tempeh, and edamame beans
• Amaranth is a gluten-free pseudocereal and a complete protein
• Buckwheat is another gluten-free pseudocereal and a complete protein
• Quinoa, a gluten-free pseudocereal, is a complete protein, although described as "nearly complete" due to its limiting essential amino acid content
• Chia seeds are tiny, round seeds that are a complete protein
• Spirulina, a supplement made from blue-green algae, is a complete protein
• Lentils are not a complete protein; they lack methionine like most plant proteins

Food Combination Examples for Obtaining All Nine Essential Amino Acids

• Beans (pulses) and grains are incomplete proteins, combined they provide all nine essential amino acids
• Rice (brown and white) and several other grains are low in lysine but high in methionine
• Beans are high in lysine but low in methionine
• Combining rice and beans allows adequate intake, as well as the remaining seven essential amino acids, counting as a complete protein

Food combination examples

• Whole grains with nuts or seeds (peanut (legume) butter on whole wheat toast)
• Whole grains with beans (beans and rice; hummus and pitta bread; bean-based chilli and crackers; refried beans and tortillas)
• Beans with nuts or seeds (salad with chickpeas and sunflower seeds)

Benefits of PBD's

• There are lectures from UCD Human Nutrition to discuss whether plant-based diets are good for you
• There are a look at the evidence to determine if plant-based diets are good for the planet

Environmental Advantages of Plant-Based Diets

• "Climate Change 2022" authors state that shifting to plant-based diets, rich in pulses, nuts, fruits, and vegetables, could substantially reduce greenhouse gas emissions compared to current dietary patterns in industrialized countries
• This is according to the Physicians Committee for Responsible Medicine; they are quoting the IPCC Sixth Assessment Report from Working Group III: Mitigation of Climate Change
• The Physicians Committee is dedicated to saving and improving human and animal lives through plant-based diets and ethical and effective scientific research
• Eating plant foods is more efficient and cost-effective for water usage and significantly better for the environment in terms of greenhouse gas emissions according to UCLA Sustainability
• Reducing animal-based food consumption would reduce water use by at least half, as animal husbandry utilizes more than 50% of fresh water according to UCLA Sustainability
• Plant-based diets account for 75% less in greenhouse gas emissions than those who eat >3.5 ounces of meat a day.
• A vegan diet results in significantly less harm to land, water and biodiversity according to research led by Prof Peter Scarborough at Oxford University

Environmental Disadvantages of Plant-Based Diets

• Humans have eaten meat for ~2.6 million years
• Animal protein was likely vital for the development of early hominids' larger brains
• Meat may be considered a part of human diets
• Significant Cultural traditions such as Bolognese sauce, tandoori chicken, sashimi, currywurst, and Peking duck could be lost if the world went vegan

Additional disadvantages of plant-based diets

• The impact of veganism is unclear on health, vegans have showed lower risk of heart disease, but higher risk of strokes
• vegans tend to exercise more, be non-smokers, not drink to excess, be more moderate in what they consume

Potential downsides of focusing too heavily on plants

• Clearing land for agriculture, using heavy machinery, applying synthetic fertilizers, and packaging/transporting foods all contribute to carbon emissions
• Forests, especially rainforests, cut down to grow crops lose some of their ability to act as carbon sinks
• Pesticides sprayed on plants can contaminate surface and groundwater, harming wildlife and humans
• Growing thirsty crops on a large commercial scale can stress local ecosystems

Examples of negatively impactful plants

• Corn: Fertilizer usage and monocropping
• Spinach: Use of synthetic pesticides in non-organic farming
• Avocado: Land and water usage
• Almond: Water and fertilizer usage
• Soybean: Land usage

Reasons for Adopting Plant-Based Diets

• Personal health
• Environmental concerns
• Dislike of farming animals
• Dislike of meat taste or texture
• Desire for variety in diet

Learning outcomes of this module

• Educate yourself
• Follow your own goals
• Follow the science
• Develop critical thinking skills