Plant-Based Diets: A Physician’s Guide
Julieanna Hever over at plantbaseddietitian.com has put together a fantastic guide written for The Permanente Journal targeted at physicians, with the purpose of helping them to help their patients make the transition to eating a plant-based diet.
While it certainly will benefit physicians and their patients, I found it to be a great read in general and I believe all of us would benefit from a close read of the guide.
However, the guide is a little dense and may be a little daunting for those not used to reading more technical language so this post will attempt to break it down a little and distill the most important points. A link to the full PDF can be found here! So this is my humble little attempt to get across the main messages…
The guide starts by explaining that in light of the growing scientific evidence for the health benefits of a plant-based diet, more and more health care practitioners may feel inclined to suggest to their patients that adopting a plant-based diet would be a wise lifestyle choice for them.
Plant-based diets have been associated with lowering overall and ischemic heart disease mortality; supporting sustainable weight management; reducing medication needs; lowering the risk for most chronic diseases; decreasing the incidence and severity of high-risk conditions, including obesity, hypertension, hyperlipidemia, and hyperglycemia; and even possibly reversing advanced coronary artery disease and type 2 diabetes.
The guide then goes on to list and detail some of the harmful components found in animal products:
- Saturated Fats: Well established in the medical literature as promoting cardiovascular disease.
- Dietary Cholesterol: Found almost exclusively in animal products, also associated with CVD.
- Antibiotics: 70% – 80% of antibiotics used in the USA are given to healthy livestock animals. This is the main contributor to antibiotic-resistant infections that sickened 2 million and killed 23,000 Americans in 2013.
- Insulin -like growth factor-1: A growth-promoting hormone that can encourage the proliferation of cancer.
- Heme Iron: Research suggests that excess iron is pro-oxidative and may increase colorectal cancer risk and promote atherosclerosis and reduced insulin sensitivity.
- Chemical Contaminants: Formed from high-temperature cooking of animal products. These compounds are carcinogenic, pro-inflammatory, pro-oxidative, and contributive to chronic disease.
- Carnitine: May be converted to TMAO (trimethylamine N-oxide), associated with inflammation, atherosclerosis, heart attack, stroke and death.
- Neu5Gc (N-Glycolylneuraminic acid): A compound found in meat that promotes chronic inflammation.
Next up is a list of the benefits of certain compounds found in plants such as carotenoids, glucosinolates, and flavonoids:
- Neutralizing freeradicals
- Cancer activity reduction via several mechanisms, including inhibiting tumor growth, detoxifying carcinogens, retarding cell growth, and preventing cancer formation
- Immunity enhancement
- Protection against certain diseases such as osteoporosis, some cancers, CVD, macular degeneration, and cataracts
- Optimization of serum cholesterol
Addressing the concern of some people that plant-based diets do not provide adequate nutrition, Hever quotes the Academy of Nutrition and Dietetics
Vegetarian diets, including total vegetarian or vegan diets, are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases.
Well-planned vegetarian diets are appropriate for individuals during all stages of the life cycle, including pregnancy, lactation, infancy, childhood, and adolescence, and for athletes.
The guide lists some of the nutritents typically abundant in a varied plant-based diet. It is explained that fruits and vegetables are high in fiber, potassium, magnesium, iron, folate, and vitamins C and A, pointing out that the typical American diet runs low on all of these essential nutrients.
Legumes are lauded as an excellent source of lysine, fiber, calcium, iron, zinc, and selenium.
Nuts are praised for their nutritional content, especially their essential fats, protein, fiber, vitamin E, and plant sterols. 30g to 60 of nuts per day is recommended (which incidentally matches our meal plans).
A very interesting point is then made with regards to the ideal macronutrient ratio. What should be the ratio of carbohyrates, fats and protein. It is noted that both low fat (10%) and upwards of 36% fat diets have been found to be have positive health advantages, which points to the quality of the food rather than the macronutrient ratio being the most important factor. For those interested in how our meal plans work out in this area, we go for a medium fat content that varies between 15% and 25%, usually on the higher end, with all fats coming from healthy sources, especially nuts and seeds.
For protein, The Institute of Medicine’s guidelines are mentioned, and for adults this works out at 0.8 grams per kilogram (of bodyweight) per day. One thing we know for certain at the Plant-based Plan is that getting adequate protein is never a problem when consuming a varied whole food plant-based diet! In the process of designing our meal plans we usually find that protein comes out at a minimum of about 70g per day and up to about 100g (without specifically trying to keep protein levels high), making our plans especially suitable for highly active people. This is achieved simply by including a wide range of whole plant foods and daily legumes, nuts and seeds. No supplements necessary!
An explanation of fats then follows, mentioning the essential fatty acids( polyunsaturated, including omega-3 and omega-6 fatty acids). The importance of Alpha linolenic acid is underlined and plant sources listed (flaxseeds, hemp seeds, chia seeds, leafy green vegetables (both terrestrial and marine), soybeans and soy products, walnuts, and wheat germ, as well as their respective oils, and microalgae).
Plant sources of fats may be preferable because marine sources such as those found in fatty fish may contain contaminants such as mercury, lead and cadmium and the guide warns us not to consume trans fatty acids with are now considered unsafe.
Next up is an explanation of certain micronutrients, with the concise point being made that…
All nutrients, with the exception of vitamin B12 and possibly vitamin D, which is ideally sourced from the skin’s exposure to the sun’s ultraviolet rays, can be found in plants.
Then some micronutrients are looked at more closely, here are the key points:
- Vitamin B12: Taking a supplement is the most reliable way of avoiding a deficiency.
- Vitamin D: Created naturally in the body through sun exposure. If patients have sub-optimal levels, emphasising food sources and supplements may be helpful.
- Calcium: Important for bone mineral optimization. Good plant sources include leafy green vegetables, especially bok choy, broccoli, napa cabbage, collard greens, dandelion greens, kale, turnip greens, and watercress, as well as fortified plant milks, calcium-set tofu, dried figs, sesame seeds and tahini, tempeh, almonds and almond butter, oranges, sweet potatoes, and beans.
- Vitamin D levels in the blood must be adequate for optimal calcium absorbtion and calcium absorbtion is more important than the amount of calcium consumed. Phytates found in whole grains, beans, seeds, nuts, and wheat bran can bind to calcium and prevent it being absorbed properly. Soaking, sprouting and leavening help with this problem.
- Emphasising food variety helps with calcium absorbtoion.
- Too much sodium, protein, caffeine and phosphorus may cause calcium to be excreted.
- Iron: It is recommended that vegans and vegetarians consume slighty more iron than non-vegetarians. Leafy greens, legumes, soy products, dark chocolate, blackstrap molasses, sesame seeds, tahini, pumpkin seeds, sunflower seeds, raisins, prunes, and cashews are good sources, and the guides suggests eating iron-rich foods in combination with foods high in vitamin C and organic acids to improve absorption.
- Iodine: Consuming iodine is important to avoid thyroid issues. Iodized salt and sea vegetables are recommended sources, especially dulse and nori. A half-teaspoon of iodized salt provides the daily recommended dose.
- Selenium: A potent antioxidant that protects against cellular damage and also plays a role in thyroid hormone regulation, reproduction, and dialpha nucleic acid (DNA) synthesis. Plant-based sources include whole grains, legumes, vegetables, seeds, and nuts, especially brazil nuts.
- Zinc: Important for immune function and wound healing; synthesis of protein and DNA; and growth and development. Legumes, cashews and other nuts, seeds, soy products, and whole grains are good sources and soaking, sprouting, leavening, and fermenting will improve absorption.
The guide then goes on to give specific advice to physicians as to how to begin implementing changes in their patients lifestyle and diet.
Although the guide is quite dense and contains a lot of technical language it’s only a few pages long. Taking an hour to sit down and really have a good read through it would really improve the general knowledge of most planteaters out there, at the very least giving them a fundamental understanding and reasons for their own lifestyle choices which they up to now may not be able to articulate very well.